diff --git a/docs/modules/IOOption.ts.md b/docs/modules/IOOption.ts.md
index f23002cf4..bbaa40a77 100644
--- a/docs/modules/IOOption.ts.md
+++ b/docs/modules/IOOption.ts.md
@@ -69,10 +69,13 @@ Added in v2.12.0
   - [Zero](#zero)
 - [legacy](#legacy)
   - [chain](#chain)
+  - [chainEitherK](#chaineitherk)
   - [chainFirst](#chainfirst)
   - [chainFirstEitherK](#chainfirsteitherk)
   - [chainFirstIOK](#chainfirstiok)
   - [chainIOK](#chainiok)
+  - [chainNullableK](#chainnullablek)
+  - [chainOptionK](#chainoptionk)
 - [lifting](#lifting)
   - [fromEitherK](#fromeitherk)
   - [fromIOK](#fromiok)
@@ -93,11 +96,11 @@ Added in v2.12.0
   - [matchEW](#matchew)
   - [matchW](#matchw)
 - [sequencing](#sequencing)
-  - [chainEitherK](#chaineitherk)
-  - [chainNullableK](#chainnullablek)
-  - [chainOptionK](#chainoptionk)
   - [flatMap](#flatmap)
+  - [flatMapEither](#flatmapeither)
   - [flatMapIO](#flatmapio)
+  - [flatMapNullable](#flatmapnullable)
+  - [flatMapOption](#flatmapoption)
   - [flatten](#flatten)
 - [traversing](#traversing)
   - [traverseReadonlyArrayWithIndex](#traversereadonlyarraywithindex)
@@ -663,6 +666,18 @@ export declare const chain: <A, B>(f: (a: A) => IOOption<B>) => (ma: IOOption<A>
 
 Added in v2.12.0
 
+## chainEitherK
+
+Alias of `flatMapEither`.
+
+**Signature**
+
+```ts
+export declare const chainEitherK: <E, A, B>(f: (a: A) => Either<E, B>) => (ma: IOOption<A>) => IOOption<B>
+```
+
+Added in v2.12.0
+
 ## chainFirst
 
 Alias of `tap`.
@@ -711,6 +726,32 @@ export declare const chainIOK: <A, B>(f: (a: A) => I.IO<B>) => (first: IOOption<
 
 Added in v2.12.0
 
+## chainNullableK
+
+Alias of `flatMapNullable`.
+
+**Signature**
+
+```ts
+export declare const chainNullableK: <A, B>(
+  f: (a: A) => B | null | undefined
+) => (ma: IOOption<A>) => IOOption<NonNullable<B>>
+```
+
+Added in v2.12.0
+
+## chainOptionK
+
+Alias of `flatMapOption`.
+
+**Signature**
+
+```ts
+export declare const chainOptionK: <A, B>(f: (a: A) => O.Option<B>) => (ma: IOOption<A>) => IOOption<B>
+```
+
+Added in v2.12.0
+
 # lifting
 
 ## fromEitherK
@@ -906,59 +947,66 @@ Added in v2.12.0
 
 # sequencing
 
-## chainEitherK
+## flatMap
 
 **Signature**
 
 ```ts
-export declare const chainEitherK: <E, A, B>(f: (a: A) => Either<E, B>) => (ma: IOOption<A>) => IOOption<B>
+export declare const flatMap: {
+  <A, B>(f: (a: A) => IOOption<B>): (ma: IOOption<A>) => IOOption<B>
+  <A, B>(ma: IOOption<A>, f: (a: A) => IOOption<B>): IOOption<B>
+}
 ```
 
-Added in v2.12.0
+Added in v2.14.0
 
-## chainNullableK
+## flatMapEither
 
 **Signature**
 
 ```ts
-export declare const chainNullableK: <A, B>(
-  f: (a: A) => B | null | undefined
-) => (ma: IOOption<A>) => IOOption<NonNullable<B>>
+export declare const flatMapEither: {
+  <A, B, _>(f: (a: A) => Either<_, B>): (self: IOOption<A>) => IOOption<B>
+  <A, B, _>(self: IOOption<A>, f: (a: A) => Either<_, B>): IOOption<B>
+}
 ```
 
-Added in v2.12.0
+Added in v2.16.0
 
-## chainOptionK
+## flatMapIO
 
 **Signature**
 
 ```ts
-export declare const chainOptionK: <A, B>(f: (a: A) => O.Option<B>) => (ma: IOOption<A>) => IOOption<B>
+export declare const flatMapIO: {
+  <A, B>(f: (a: A) => I.IO<B>): (self: IOOption<A>) => IOOption<B>
+  <A, B>(self: IOOption<A>, f: (a: A) => I.IO<B>): IOOption<B>
+}
 ```
 
-Added in v2.12.0
+Added in v2.16.0
 
-## flatMap
+## flatMapNullable
 
 **Signature**
 
 ```ts
-export declare const flatMap: {
-  <A, B>(f: (a: A) => IOOption<B>): (ma: IOOption<A>) => IOOption<B>
-  <A, B>(ma: IOOption<A>, f: (a: A) => IOOption<B>): IOOption<B>
+export declare const flatMapNullable: {
+  <A, B>(f: (a: A) => B | null | undefined): (self: IOOption<A>) => IOOption<B>
+  <A, B>(self: IOOption<A>, f: (a: A) => B | null | undefined): IOOption<B>
 }
 ```
 
-Added in v2.14.0
+Added in v2.16.0
 
-## flatMapIO
+## flatMapOption
 
 **Signature**
 
 ```ts
-export declare const flatMapIO: {
-  <A, B>(f: (a: A) => I.IO<B>): (self: IOOption<A>) => IOOption<B>
-  <A, B>(self: IOOption<A>, f: (a: A) => I.IO<B>): IOOption<B>
+export declare const flatMapOption: {
+  <A, B>(f: (a: A) => O.Option<B>): (self: IOOption<A>) => IOOption<B>
+  <A, B>(self: IOOption<A>, f: (a: A) => O.Option<B>): IOOption<B>
 }
 ```
 
diff --git a/docs/modules/ReaderTaskEither.ts.md b/docs/modules/ReaderTaskEither.ts.md
index 6a448f2a6..7b30da0e9 100644
--- a/docs/modules/ReaderTaskEither.ts.md
+++ b/docs/modules/ReaderTaskEither.ts.md
@@ -117,10 +117,14 @@ Added in v2.0.0
   - [chainFirstTaskEitherKW](#chainfirsttaskeitherkw)
   - [chainFirstTaskK](#chainfirsttaskk)
   - [chainFirstW](#chainfirstw)
+  - [chainIOEitherK](#chainioeitherk)
+  - [chainIOEitherKW](#chainioeitherkw)
   - [chainIOK](#chainiok)
   - [chainNullableK](#chainnullablek)
   - [chainOptionK](#chainoptionk)
   - [chainOptionKW](#chainoptionkw)
+  - [chainReaderEitherK](#chainreadereitherk)
+  - [chainReaderEitherKW](#chainreadereitherkw)
   - [chainReaderIOK](#chainreaderiok)
   - [chainReaderIOKW](#chainreaderiokw)
   - [chainReaderK](#chainreaderk)
@@ -164,16 +168,14 @@ Added in v2.0.0
   - [matchEW](#matchew)
   - [matchW](#matchw)
 - [sequencing](#sequencing)
-  - [chainIOEitherK](#chainioeitherk)
-  - [chainIOEitherKW](#chainioeitherkw)
-  - [chainReaderEitherK](#chainreadereitherk)
-  - [chainReaderEitherKW](#chainreadereitherkw)
   - [flatMap](#flatmap)
   - [flatMapEither](#flatmapeither)
   - [flatMapIO](#flatmapio)
+  - [flatMapIOEither](#flatmapioeither)
   - [flatMapNullable](#flatmapnullable)
   - [flatMapOption](#flatmapoption)
   - [flatMapReader](#flatmapreader)
+  - [flatMapReaderEither](#flatmapreadereither)
   - [flatMapReaderIO](#flatmapreaderio)
   - [flatMapReaderTask](#flatmapreadertask)
   - [flatMapTask](#flatmaptask)
@@ -1619,6 +1621,38 @@ export declare const chainFirstW: <R2, E2, A, B>(
 
 Added in v2.8.0
 
+## chainIOEitherK
+
+Alias of `flatMapIOEither`.
+
+**Signature**
+
+```ts
+export declare const chainIOEitherK: <E, A, B>(
+  f: (a: A) => IOEither<E, B>
+) => <R>(ma: ReaderTaskEither<R, E, A>) => ReaderTaskEither<R, E, B>
+```
+
+Added in v2.4.0
+
+## chainIOEitherKW
+
+Alias of `flatMapIOEither`.
+
+Less strict version of [`chainIOEitherK`](#chainioeitherk).
+
+The `W` suffix (short for **W**idening) means that the environment types and the error types will be merged.
+
+**Signature**
+
+```ts
+export declare const chainIOEitherKW: <E2, A, B>(
+  f: (a: A) => IOEither<E2, B>
+) => <R, E1>(ma: ReaderTaskEither<R, E1, A>) => ReaderTaskEither<R, E2 | E1, B>
+```
+
+Added in v2.6.1
+
 ## chainIOK
 
 Alias of `flatMapIO`.
@@ -1677,6 +1711,38 @@ export declare const chainOptionKW: <E2>(
 
 Added in v2.13.2
 
+## chainReaderEitherK
+
+Alias of `flatMapReaderEither`.
+
+**Signature**
+
+```ts
+export declare const chainReaderEitherK: <R, E, A, B>(
+  f: (a: A) => ReaderEither<R, E, B>
+) => (ma: ReaderTaskEither<R, E, A>) => ReaderTaskEither<R, E, B>
+```
+
+Added in v2.11.0
+
+## chainReaderEitherKW
+
+Alias of `flatMapReaderEither`.
+
+Less strict version of [`chainReaderEitherK`](#chainreadereitherk).
+
+The `W` suffix (short for **W**idening) means that the environment types and the error types will be merged.
+
+**Signature**
+
+```ts
+export declare const chainReaderEitherKW: <R2, E2, A, B>(
+  f: (a: A) => ReaderEither<R2, E2, B>
+) => <R1, E1>(ma: ReaderTaskEither<R1, E1, A>) => ReaderTaskEither<R1 & R2, E2 | E1, B>
+```
+
+Added in v2.11.0
+
 ## chainReaderIOK
 
 Alias of `flatMapReaderIO`.
@@ -2219,62 +2285,6 @@ Added in v2.10.0
 
 # sequencing
 
-## chainIOEitherK
-
-**Signature**
-
-```ts
-export declare const chainIOEitherK: <E, A, B>(
-  f: (a: A) => IOEither<E, B>
-) => <R>(ma: ReaderTaskEither<R, E, A>) => ReaderTaskEither<R, E, B>
-```
-
-Added in v2.4.0
-
-## chainIOEitherKW
-
-Less strict version of [`chainIOEitherK`](#chainioeitherk).
-
-The `W` suffix (short for **W**idening) means that the environment types and the error types will be merged.
-
-**Signature**
-
-```ts
-export declare const chainIOEitherKW: <E2, A, B>(
-  f: (a: A) => IOEither<E2, B>
-) => <R, E1>(ma: ReaderTaskEither<R, E1, A>) => ReaderTaskEither<R, E2 | E1, B>
-```
-
-Added in v2.6.1
-
-## chainReaderEitherK
-
-**Signature**
-
-```ts
-export declare const chainReaderEitherK: <R, E, A, B>(
-  f: (a: A) => ReaderEither<R, E, B>
-) => (ma: ReaderTaskEither<R, E, A>) => ReaderTaskEither<R, E, B>
-```
-
-Added in v2.11.0
-
-## chainReaderEitherKW
-
-Less strict version of [`chainReaderEitherK`](#chainreadereitherk).
-
-The `W` suffix (short for **W**idening) means that the environment types and the error types will be merged.
-
-**Signature**
-
-```ts
-export declare const chainReaderEitherKW: <R2, E2, A, B>(
-  f: (a: A) => ReaderEither<R2, E2, B>
-) => <R1, E1>(ma: ReaderTaskEither<R1, E1, A>) => ReaderTaskEither<R1 & R2, E2 | E1, B>
-```
-
-Added in v2.11.0
-
 ## flatMap
 
 **Signature**
@@ -2320,6 +2330,19 @@ export declare const flatMapIO: {
 
 Added in v2.16.0
 
+## flatMapIOEither
+
+**Signature**
+
+```ts
+export declare const flatMapIOEither: {
+  <A, E2, B>(f: (a: A) => IOEither<E2, B>): <R, E1>(self: ReaderTaskEither<R, E1, A>) => ReaderTaskEither<R, E2 | E1, B>
+  <R, E1, A, E2, B>(self: ReaderTaskEither<R, E1, A>, f: (a: A) => IOEither<E2, B>): ReaderTaskEither<R, E1 | E2, B>
+}
+```
+
+Added in v2.16.0
+
 ## flatMapNullable
 
 **Signature**
@@ -2371,6 +2394,25 @@ export declare const flatMapReader: {
 
 Added in v2.16.0
 
+## flatMapReaderEither
+
+**Signature**
+
+```ts
+export declare const flatMapReaderEither: {
+  <A, R2, E2, B>(f: (a: A) => ReaderEither<R2, E2, B>): <R1, E1>(
+    self: ReaderTaskEither<R1, E1, A>
+  ) => ReaderTaskEither<R1 & R2, E2 | E1, B>
+  <R1, E1, A, R2, E2, B>(self: ReaderTaskEither<R1, E1, A>, f: (a: A) => ReaderEither<R2, E2, B>): ReaderTaskEither<
+    R1 & R2,
+    E1 | E2,
+    B
+  >
+}
+```
+
+Added in v2.16.0
+
 ## flatMapReaderIO
 
 **Signature**
diff --git a/docs/modules/StateReaderTaskEither.ts.md b/docs/modules/StateReaderTaskEither.ts.md
index cd4995e7a..8f558905b 100644
--- a/docs/modules/StateReaderTaskEither.ts.md
+++ b/docs/modules/StateReaderTaskEither.ts.md
@@ -77,6 +77,8 @@ Added in v2.0.0
   - [Pointed](#pointed)
 - [legacy](#legacy)
   - [chain](#chain)
+  - [chainEitherK](#chaineitherk)
+  - [chainEitherKW](#chaineitherkw)
   - [chainFirst](#chainfirst)
   - [chainFirstEitherK](#chainfirsteitherk)
   - [chainFirstEitherKW](#chainfirsteitherkw)
@@ -85,11 +87,19 @@ Added in v2.0.0
   - [chainFirstReaderKW](#chainfirstreaderkw)
   - [chainFirstTaskK](#chainfirsttaskk)
   - [chainFirstW](#chainfirstw)
+  - [chainIOEitherK](#chainioeitherk)
+  - [chainIOEitherKW](#chainioeitherkw)
   - [chainIOK](#chainiok)
+  - [chainOptionK](#chainoptionk)
+  - [chainOptionKW](#chainoptionkw)
   - [chainReaderK](#chainreaderk)
   - [chainReaderKW](#chainreaderkw)
+  - [chainReaderTaskEitherK](#chainreadertaskeitherk)
+  - [chainReaderTaskEitherKW](#chainreadertaskeitherkw)
+  - [chainStateK](#chainstatek)
   - [chainTaskEitherK](#chaintaskeitherk)
   - [chainTaskEitherKW](#chaintaskeitherkw)
+  - [chainTaskK](#chaintaskk)
   - [chainW](#chainw)
 - [lifting](#lifting)
   - [fromEitherK](#fromeitherk)
@@ -111,19 +121,14 @@ Added in v2.0.0
 - [model](#model)
   - [StateReaderTaskEither (interface)](#statereadertaskeither-interface)
 - [sequencing](#sequencing)
-  - [chainEitherK](#chaineitherk)
-  - [chainEitherKW](#chaineitherkw)
-  - [chainIOEitherK](#chainioeitherk)
-  - [chainIOEitherKW](#chainioeitherkw)
-  - [chainOptionK](#chainoptionk)
-  - [chainOptionKW](#chainoptionkw)
-  - [chainReaderTaskEitherK](#chainreadertaskeitherk)
-  - [chainReaderTaskEitherKW](#chainreadertaskeitherkw)
-  - [chainStateK](#chainstatek)
-  - [chainTaskK](#chaintaskk)
   - [flatMap](#flatmap)
+  - [flatMapEither](#flatmapeither)
   - [flatMapIO](#flatmapio)
+  - [flatMapIOEither](#flatmapioeither)
+  - [flatMapOption](#flatmapoption)
   - [flatMapReader](#flatmapreader)
+  - [flatMapReaderTaskEither](#flatmapreadertaskeither)
+  - [flatMapState](#flatmapstate)
   - [flatMapTask](#flatmaptask)
   - [flatMapTaskEither](#flatmaptaskeither)
   - [flatten](#flatten)
@@ -873,6 +878,40 @@ export declare const chain: <S, R, E, A, B>(
 
 Added in v2.0.0
 
+## chainEitherK
+
+Alias of `flatMapEither`.
+
+**Signature**
+
+```ts
+export declare const chainEitherK: <E, A, B>(
+  f: (a: A) => E.Either<E, B>
+) => <S, R>(ma: StateReaderTaskEither<S, R, E, A>) => StateReaderTaskEither<S, R, E, B>
+```
+
+Added in v2.4.0
+
+## chainEitherKW
+
+Alias of `flatMapEither`.
+
+Less strict version of [`chainEitherK`](#chaineitherk).
+
+The `W` suffix (short for **W**idening) means that the error types will be merged.
+
+The `W` suffix (short for **W**idening) means that the environment types and the error types will be merged.
+
+**Signature**
+
+```ts
+export declare const chainEitherKW: <E2, A, B>(
+  f: (a: A) => E.Either<E2, B>
+) => <S, R, E1>(ma: StateReaderTaskEither<S, R, E1, A>) => StateReaderTaskEither<S, R, E2 | E1, B>
+```
+
+Added in v2.6.1
+
 ## chainFirst
 
 Alias of `tap`.
@@ -993,6 +1032,36 @@ export declare const chainFirstW: <S, R2, E2, A, B>(
 
 Added in v2.8.0
 
+## chainIOEitherK
+
+Alias of `flatMapIOEither`.
+
+**Signature**
+
+```ts
+export declare const chainIOEitherK: <E, A, B>(
+  f: (a: A) => IOEither<E, B>
+) => <S, R>(ma: StateReaderTaskEither<S, R, E, A>) => StateReaderTaskEither<S, R, E, B>
+```
+
+Added in v2.4.0
+
+## chainIOEitherKW
+
+Alias of `flatMapIOEither`.
+
+Less strict version of [`chainIOEitherK`](#chainioeitherk).
+
+**Signature**
+
+```ts
+export declare const chainIOEitherKW: <E2, A, B>(
+  f: (a: A) => IOEither<E2, B>
+) => <S, R, E1>(ma: StateReaderTaskEither<S, R, E1, A>) => StateReaderTaskEither<S, R, E2 | E1, B>
+```
+
+Added in v2.6.1
+
 ## chainIOK
 
 Alias of `flatMapIO`.
@@ -1007,6 +1076,42 @@ export declare const chainIOK: <A, B>(
 
 Added in v2.10.0
 
+## chainOptionK
+
+Use `flatMapOption`.
+
+**Signature**
+
+```ts
+export declare const chainOptionK: <E>(
+  onNone: LazyArg<E>
+) => <A, B>(
+  f: (a: A) => Option<B>
+) => <S, R>(ma: StateReaderTaskEither<S, R, E, A>) => StateReaderTaskEither<S, R, E, B>
+```
+
+Added in v2.10.0
+
+## chainOptionKW
+
+Use `flatMapOption`.
+
+Less strict version of [`chainOptionK`](#chainoptionk).
+
+The `W` suffix (short for **W**idening) means that the error types will be merged.
+
+**Signature**
+
+```ts
+export declare const chainOptionKW: <E2>(
+  onNone: LazyArg<E2>
+) => <A, B>(
+  f: (a: A) => Option<B>
+) => <S, R, E1>(ma: StateReaderTaskEither<S, R, E1, A>) => StateReaderTaskEither<S, R, E2 | E1, B>
+```
+
+Added in v2.13.2
+
 ## chainReaderK
 
 Alias of `flatMapReader`.
@@ -1039,6 +1144,50 @@ export declare const chainReaderKW: <A, R1, B>(
 
 Added in v2.11.0
 
+## chainReaderTaskEitherK
+
+Alias of `flatMapReaderTaskEither`.
+
+**Signature**
+
+```ts
+export declare const chainReaderTaskEitherK: <R, E, A, B>(
+  f: (a: A) => RTE.ReaderTaskEither<R, E, B>
+) => <S>(ma: StateReaderTaskEither<S, R, E, A>) => StateReaderTaskEither<S, R, E, B>
+```
+
+Added in v2.4.0
+
+## chainReaderTaskEitherKW
+
+Alias of `flatMapReaderTaskEither`.
+
+Less strict version of [`chainReaderTaskEitherK`](#chainreadertaskeitherk).
+
+**Signature**
+
+```ts
+export declare const chainReaderTaskEitherKW: <R, E2, A, B>(
+  f: (a: A) => RTE.ReaderTaskEither<R, E2, B>
+) => <S, E1>(ma: StateReaderTaskEither<S, R, E1, A>) => StateReaderTaskEither<S, R, E2 | E1, B>
+```
+
+Added in v2.6.1
+
+## chainStateK
+
+Alias of `flatMapState`.
+
+**Signature**
+
+```ts
+export declare const chainStateK: <A, S, B>(
+  f: (a: A) => State<S, B>
+) => <R, E>(ma: StateReaderTaskEither<S, R, E, A>) => StateReaderTaskEither<S, R, E, B>
+```
+
+Added in v2.11.0
+
 ## chainTaskEitherK
 
 Alias of `flatMapTaskEither`.
@@ -1069,6 +1218,20 @@ export declare const chainTaskEitherKW: <E2, A, B>(
 
 Added in v2.6.1
 
+## chainTaskK
+
+Alias of `flatMapTask`.
+
+**Signature**
+
+```ts
+export declare const chainTaskK: <A, B>(
+  f: (a: A) => Task<B>
+) => <S, R, E>(first: StateReaderTaskEither<S, R, E, A>) => StateReaderTaskEither<S, R, E, B>
+```
+
+Added in v2.10.0
+
 ## chainW
 
 Alias of `flatMap`.
@@ -1302,192 +1465,144 @@ Added in v2.0.0
 
 # sequencing
 
-## chainEitherK
-
-**Signature**
-
-```ts
-export declare const chainEitherK: <E, A, B>(
-  f: (a: A) => E.Either<E, B>
-) => <S, R>(ma: StateReaderTaskEither<S, R, E, A>) => StateReaderTaskEither<S, R, E, B>
-```
-
-Added in v2.4.0
-
-## chainEitherKW
-
-Less strict version of [`chainEitherK`](#chaineitherk).
-
-The `W` suffix (short for **W**idening) means that the error types will be merged.
-
-The `W` suffix (short for **W**idening) means that the environment types and the error types will be merged.
-
-**Signature**
-
-```ts
-export declare const chainEitherKW: <E2, A, B>(
-  f: (a: A) => E.Either<E2, B>
-) => <S, R, E1>(ma: StateReaderTaskEither<S, R, E1, A>) => StateReaderTaskEither<S, R, E2 | E1, B>
-```
-
-Added in v2.6.1
-
-## chainIOEitherK
-
-**Signature**
-
-```ts
-export declare const chainIOEitherK: <E, A, B>(
-  f: (a: A) => IOEither<E, B>
-) => <S, R>(ma: StateReaderTaskEither<S, R, E, A>) => StateReaderTaskEither<S, R, E, B>
-```
-
-Added in v2.4.0
-
-## chainIOEitherKW
-
-Less strict version of [`chainIOEitherK`](#chainioeitherk).
-
-**Signature**
-
-```ts
-export declare const chainIOEitherKW: <E2, A, B>(
-  f: (a: A) => IOEither<E2, B>
-) => <S, R, E1>(ma: StateReaderTaskEither<S, R, E1, A>) => StateReaderTaskEither<S, R, E2 | E1, B>
-```
-
-Added in v2.6.1
-
-## chainOptionK
+## flatMap
 
 **Signature**
 
 ```ts
-export declare const chainOptionK: <E>(
-  onNone: LazyArg<E>
-) => <A, B>(
-  f: (a: A) => Option<B>
-) => <S, R>(ma: StateReaderTaskEither<S, R, E, A>) => StateReaderTaskEither<S, R, E, B>
+export declare const flatMap: {
+  <A, S, R2, E2, B>(f: (a: A) => StateReaderTaskEither<S, R2, E2, B>): <R1, E1>(
+    ma: StateReaderTaskEither<S, R1, E1, A>
+  ) => StateReaderTaskEither<S, R1 & R2, E2 | E1, B>
+  <S, R1, E1, A, R2, E2, B>(
+    ma: StateReaderTaskEither<S, R1, E1, A>,
+    f: (a: A) => StateReaderTaskEither<S, R2, E2, B>
+  ): StateReaderTaskEither<S, R1 & R2, E1 | E2, B>
+}
 ```
 
-Added in v2.10.0
-
-## chainOptionKW
-
-Less strict version of [`chainOptionK`](#chainoptionk).
+Added in v2.14.0
 
-The `W` suffix (short for **W**idening) means that the error types will be merged.
+## flatMapEither
 
 **Signature**
 
 ```ts
-export declare const chainOptionKW: <E2>(
-  onNone: LazyArg<E2>
-) => <A, B>(
-  f: (a: A) => Option<B>
-) => <S, R, E1>(ma: StateReaderTaskEither<S, R, E1, A>) => StateReaderTaskEither<S, R, E2 | E1, B>
+export declare const flatMapEither: {
+  <A, E2, B>(f: (a: A) => E.Either<E2, B>): <S, R, E1>(
+    self: StateReaderTaskEither<S, R, E1, A>
+  ) => StateReaderTaskEither<S, R, E2 | E1, B>
+  <S, R, E1, A, E2, B>(self: StateReaderTaskEither<S, R, E1, A>, f: (a: A) => E.Either<E2, B>): StateReaderTaskEither<
+    S,
+    R,
+    E1 | E2,
+    B
+  >
+}
 ```
 
-Added in v2.13.2
+Added in v2.16.0
 
-## chainReaderTaskEitherK
+## flatMapIO
 
 **Signature**
 
 ```ts
-export declare const chainReaderTaskEitherK: <R, E, A, B>(
-  f: (a: A) => RTE.ReaderTaskEither<R, E, B>
-) => <S>(ma: StateReaderTaskEither<S, R, E, A>) => StateReaderTaskEither<S, R, E, B>
+export declare const flatMapIO: {
+  <A, B>(f: (a: A) => IO<B>): <S, R, E>(self: StateReaderTaskEither<S, R, E, A>) => StateReaderTaskEither<S, R, E, B>
+  <S, R, E, A, B>(self: StateReaderTaskEither<S, R, E, A>, f: (a: A) => IO<B>): StateReaderTaskEither<S, R, E, B>
+}
 ```
 
-Added in v2.4.0
-
-## chainReaderTaskEitherKW
+Added in v2.16.0
 
-Less strict version of [`chainReaderTaskEitherK`](#chainreadertaskeitherk).
+## flatMapIOEither
 
 **Signature**
 
 ```ts
-export declare const chainReaderTaskEitherKW: <R, E2, A, B>(
-  f: (a: A) => RTE.ReaderTaskEither<R, E2, B>
-) => <S, E1>(ma: StateReaderTaskEither<S, R, E1, A>) => StateReaderTaskEither<S, R, E2 | E1, B>
+export declare const flatMapIOEither: {
+  <A, E2, B>(f: (a: A) => IOEither<E2, B>): <S, R, E1>(
+    self: StateReaderTaskEither<S, R, E1, A>
+  ) => StateReaderTaskEither<S, R, E2 | E1, B>
+  <S, R, E1, A, E2, B>(self: StateReaderTaskEither<S, R, E1, A>, f: (a: A) => IOEither<E2, B>): StateReaderTaskEither<
+    S,
+    R,
+    E1 | E2,
+    B
+  >
+}
 ```
 
-Added in v2.6.1
+Added in v2.16.0
 
-## chainStateK
+## flatMapOption
 
 **Signature**
 
 ```ts
-export declare const chainStateK: <A, S, B>(
-  f: (a: A) => State<S, B>
-) => <R, E>(ma: StateReaderTaskEither<S, R, E, A>) => StateReaderTaskEither<S, R, E, B>
+export declare const flatMapOption: {
+  <A, E2, B>(f: (a: A) => Option<B>, onNone: (a: A) => E2): <S, R, E1>(
+    self: StateReaderTaskEither<S, R, E1, A>
+  ) => StateReaderTaskEither<S, R, E2 | E1, B>
+  <S, R, E1, A, E2, B>(
+    self: StateReaderTaskEither<S, R, E1, A>,
+    f: (a: A) => Option<B>,
+    onNone: (a: A) => E2
+  ): StateReaderTaskEither<S, R, E1 | E2, B>
+}
 ```
 
-Added in v2.11.0
-
-## chainTaskK
+Added in v2.16.0
 
-Alias of `flatMapTask`.
+## flatMapReader
 
 **Signature**
 
 ```ts
-export declare const chainTaskK: <A, B>(
-  f: (a: A) => Task<B>
-) => <S, R, E>(first: StateReaderTaskEither<S, R, E, A>) => StateReaderTaskEither<S, R, E, B>
+export declare const flatMapReader: {
+  <A, R2, B>(f: (a: A) => R.Reader<R2, B>): <S, R1, E>(
+    self: StateReaderTaskEither<S, R1, E, A>
+  ) => StateReaderTaskEither<S, R1 & R2, E, B>
+  <S, R1, E, A, R2, B>(self: StateReaderTaskEither<S, R1, E, A>, f: (a: A) => R.Reader<R2, B>): StateReaderTaskEither<
+    S,
+    R1 & R2,
+    E,
+    B
+  >
+}
 ```
 
-Added in v2.10.0
+Added in v2.16.0
 
-## flatMap
+## flatMapReaderTaskEither
 
 **Signature**
 
 ```ts
-export declare const flatMap: {
-  <A, S, R2, E2, B>(f: (a: A) => StateReaderTaskEither<S, R2, E2, B>): <R1, E1>(
-    ma: StateReaderTaskEither<S, R1, E1, A>
+export declare const flatMapReaderTaskEither: {
+  <A, R2, E2, B>(f: (a: A) => RTE.ReaderTaskEither<R2, E2, B>): <S, R1, E1>(
+    self: StateReaderTaskEither<S, R1, E1, A>
   ) => StateReaderTaskEither<S, R1 & R2, E2 | E1, B>
   <S, R1, E1, A, R2, E2, B>(
-    ma: StateReaderTaskEither<S, R1, E1, A>,
-    f: (a: A) => StateReaderTaskEither<S, R2, E2, B>
+    self: StateReaderTaskEither<S, R1, E1, A>,
+    f: (a: A) => RTE.ReaderTaskEither<R2, E2, B>
   ): StateReaderTaskEither<S, R1 & R2, E1 | E2, B>
 }
 ```
 
-Added in v2.14.0
-
-## flatMapIO
-
-**Signature**
-
-```ts
-export declare const flatMapIO: {
-  <A, B>(f: (a: A) => IO<B>): <S, R, E>(self: StateReaderTaskEither<S, R, E, A>) => StateReaderTaskEither<S, R, E, B>
-  <S, R, E, A, B>(self: StateReaderTaskEither<S, R, E, A>, f: (a: A) => IO<B>): StateReaderTaskEither<S, R, E, B>
-}
-```
-
 Added in v2.16.0
 
-## flatMapReader
+## flatMapState
 
 **Signature**
 
 ```ts
-export declare const flatMapReader: {
-  <A, R2, B>(f: (a: A) => R.Reader<R2, B>): <S, R1, E>(
-    self: StateReaderTaskEither<S, R1, E, A>
-  ) => StateReaderTaskEither<S, R1 & R2, E, B>
-  <S, R1, E, A, R2, B>(self: StateReaderTaskEither<S, R1, E, A>, f: (a: A) => R.Reader<R2, B>): StateReaderTaskEither<
-    S,
-    R1 & R2,
-    E,
-    B
-  >
+export declare const flatMapState: {
+  <S, A, B>(f: (a: A) => State<S, B>): <R, E>(
+    self: StateReaderTaskEither<S, R, E, A>
+  ) => StateReaderTaskEither<S, R, E, B>
+  <S, R, E, A, B>(self: StateReaderTaskEither<S, R, E, A>, f: (a: A) => State<S, B>): StateReaderTaskEither<S, R, E, B>
 }
 ```
 
diff --git a/docs/modules/TaskEither.ts.md b/docs/modules/TaskEither.ts.md
index 519560854..c26e0f16a 100644
--- a/docs/modules/TaskEither.ts.md
+++ b/docs/modules/TaskEither.ts.md
@@ -101,11 +101,15 @@ Added in v2.0.0
   - [chainFirstIOK](#chainfirstiok)
   - [chainFirstTaskK](#chainfirsttaskk)
   - [chainFirstW](#chainfirstw)
+  - [chainIOEitherK](#chainioeitherk)
+  - [chainIOEitherKW](#chainioeitherkw)
   - [chainIOK](#chainiok)
   - [chainNullableK](#chainnullablek)
   - [chainOptionK](#chainoptionk)
   - [chainOptionKW](#chainoptionkw)
   - [chainTaskK](#chaintaskk)
+  - [chainTaskOptionK](#chaintaskoptionk)
+  - [chainTaskOptionKW](#chaintaskoptionkw)
   - [chainW](#chainw)
   - [fromNullableK](#fromnullablek)
   - [fromOptionK](#fromoptionk)
@@ -136,16 +140,14 @@ Added in v2.0.0
   - [matchEW](#matchew)
   - [matchW](#matchw)
 - [sequencing](#sequencing)
-  - [chainIOEitherK](#chainioeitherk)
-  - [chainIOEitherKW](#chainioeitherkw)
-  - [chainTaskOptionK](#chaintaskoptionk)
-  - [chainTaskOptionKW](#chaintaskoptionkw)
   - [flatMap](#flatmap)
   - [flatMapEither](#flatmapeither)
   - [flatMapIO](#flatmapio)
+  - [flatMapIOEither](#flatmapioeither)
   - [flatMapNullable](#flatmapnullable)
   - [flatMapOption](#flatmapoption)
   - [flatMapTask](#flatmaptask)
+  - [flatMapTaskOption](#flatmaptaskoption)
   - [flatten](#flatten)
   - [flattenW](#flattenw)
 - [traversing](#traversing)
@@ -1343,6 +1345,38 @@ export declare const chainFirstW: <E2, A, B>(
 
 Added in v2.8.0
 
+## chainIOEitherK
+
+Alias of `flatMapIOEither`.
+
+**Signature**
+
+```ts
+export declare const chainIOEitherK: <E, A, B>(
+  f: (a: A) => IOEither<E, B>
+) => (ma: TaskEither<E, A>) => TaskEither<E, B>
+```
+
+Added in v2.4.0
+
+## chainIOEitherKW
+
+Alias of `flatMapIOEither`.
+
+Less strict version of [`chainIOEitherK`](#chainioeitherk).
+
+The `W` suffix (short for **W**idening) means that the error types will be merged.
+
+**Signature**
+
+```ts
+export declare const chainIOEitherKW: <E2, A, B>(
+  f: (a: A) => IOEither<E2, B>
+) => <E1>(ma: TaskEither<E1, A>) => TaskEither<E2 | E1, B>
+```
+
+Added in v2.6.1
+
 ## chainIOK
 
 Alias of `flatMapIO`.
@@ -1409,6 +1443,36 @@ export declare const chainTaskK: <A, B>(f: (a: A) => T.Task<B>) => <E>(first: Ta
 
 Added in v2.10.0
 
+## chainTaskOptionK
+
+Use `flatMapTaskOption`.
+
+**Signature**
+
+```ts
+export declare const chainTaskOptionK: <E>(
+  onNone: LazyArg<E>
+) => <A, B>(f: (a: A) => TaskOption<B>) => (ma: TaskEither<E, A>) => TaskEither<E, B>
+```
+
+Added in v2.11.0
+
+## chainTaskOptionKW
+
+Use `flatMapTaskOption`.
+
+The `W` suffix (short for **W**idening) means that the error types will be merged.
+
+**Signature**
+
+```ts
+export declare const chainTaskOptionKW: <E2>(
+  onNone: LazyArg<E2>
+) => <A, B>(f: (a: A) => TaskOption<B>) => <E1>(ma: TaskEither<E1, A>) => TaskEither<E2 | E1, B>
+```
+
+Added in v2.12.3
+
 ## chainW
 
 Alias of `flatMap`.
@@ -1752,60 +1816,6 @@ Added in v2.10.0
 
 # sequencing
 
-## chainIOEitherK
-
-**Signature**
-
-```ts
-export declare const chainIOEitherK: <E, A, B>(
-  f: (a: A) => IOEither<E, B>
-) => (ma: TaskEither<E, A>) => TaskEither<E, B>
-```
-
-Added in v2.4.0
-
-## chainIOEitherKW
-
-Less strict version of [`chainIOEitherK`](#chainioeitherk).
-
-The `W` suffix (short for **W**idening) means that the error types will be merged.
-
-**Signature**
-
-```ts
-export declare const chainIOEitherKW: <E2, A, B>(
-  f: (a: A) => IOEither<E2, B>
-) => <E1>(ma: TaskEither<E1, A>) => TaskEither<E2 | E1, B>
-```
-
-Added in v2.6.1
-
-## chainTaskOptionK
-
-**Signature**
-
-```ts
-export declare const chainTaskOptionK: <E>(
-  onNone: LazyArg<E>
-) => <A, B>(f: (a: A) => TaskOption<B>) => (ma: TaskEither<E, A>) => TaskEither<E, B>
-```
-
-Added in v2.11.0
-
-## chainTaskOptionKW
-
-The `W` suffix (short for **W**idening) means that the error types will be merged.
-
-**Signature**
-
-```ts
-export declare const chainTaskOptionKW: <E2>(
-  onNone: LazyArg<E2>
-) => <A, B>(f: (a: A) => TaskOption<B>) => <E1>(ma: TaskEither<E1, A>) => TaskEither<E2 | E1, B>
-```
-
-Added in v2.12.3
-
 ## flatMap
 
 **Signature**
@@ -1845,6 +1855,19 @@ export declare const flatMapIO: {
 
 Added in v2.15.0
 
+## flatMapIOEither
+
+**Signature**
+
+```ts
+export declare const flatMapIOEither: {
+  <A, E2, B>(f: (a: A) => IOEither<E2, B>): <E1>(self: TaskEither<E1, A>) => TaskEither<E2 | E1, B>
+  <E1, A, E2, B>(self: TaskEither<E1, A>, f: (a: A) => IOEither<E2, B>): TaskEither<E1 | E2, B>
+}
+```
+
+Added in v2.16.0
+
 ## flatMapNullable
 
 **Signature**
@@ -1889,6 +1912,19 @@ export declare const flatMapTask: {
 
 Added in v2.16.0
 
+## flatMapTaskOption
+
+**Signature**
+
+```ts
+export declare const flatMapTaskOption: {
+  <A, E2, B>(f: (a: A) => TaskOption<B>, onNone: (a: A) => E2): <E1>(self: TaskEither<E1, A>) => TaskEither<E2 | E1, B>
+  <E1, A, E2, B>(self: TaskEither<E1, A>, f: (a: A) => TaskOption<B>, onNone: (a: A) => E2): TaskEither<E1 | E2, B>
+}
+```
+
+Added in v2.16.0
+
 ## flatten
 
 **Signature**