Possible modules to include

For adding new modules, some restrictions apply:

1. code license must be GPL-3.0-or-later compatible (this means GPL-3.0-only is not allowed)
2. artwork must allow redistribution
3. licenses must use SPDX symbols when possible
4. when a license is uncertain, use ???
5. everything must be in alphabetical order
6. once a plugin is checked and added to cardinal, it gets removed from the list

Code Licenses

First, let's filter by code license.
We can mention non-compatible plugins here as a way to know when something is good but incompatible.
Maybe at some point the authors change this, who knows.

Plugin	License	One good reason to include it
3HR	✔️ GPL-3.0-or-later	Various interesting delay/filter/oscillator/cv utils
4ms	✔️ GPL-3.0-or-later	Ports of the 4ms eurorack modules. Includes the MetaModule hub module
AetrionModular	✔️ GPL-3.0-or-later	Polyphonic cv/gate recorder/sequencer
Agave	✔️ CC0-1.0	Filters and noise generator
Ahornberg	✔️ GPL-3.0-or-later	Various utilities
Airwindows Suite for Rack	✔️ MIT	All the 300+ Airwindows effects imported to VCV Rack as a single module. Numerous workhorses and specialty plugins alike.
Alikins	✔️ GPL-3.0-or-later	Handy CV utilities
AlliewayAudio_Freebies	✔️ GPL-3.0-or-later	1:1 digital recreation of Mannequins 'Cold Mac' esoteric macro-utility
alto777_LFSR	✔️ BSD-3-Clause	Mostly sequencers (Rack 1)
aridacity	✔️ BSD-3-Clause	Clock Divider, Bit Crusher and Clip Limiter
AuraAudio	✔️ MIT	Visualizer
az	✔️ GPL-3.0-or-later	Sequencer/Arpeggiator and slime mold visualizer
Atelier	✔️ GPL-3.0-or-later	Highly requested, great sounding module. A fork of Plaits/Macro Oscillator
Bark	❌ Custom-non-FOSS	Modulators, polyphonic S&H and utils. ❌ not actually BSD-4-Clause license, but some custom 4th clause that prohibits commercial use: problematic!
captvolt	✔️ GPL-3.0-or-later	Raw SID 6581/8580 chip emulation using ReSID engine
CatroBlanco	✔️ BSD-3-Clause	7 blank panels that react to CV input
ChordController	✔️ MIT	Builds control voltages for a chord of up to six notes from one CV input (Rack 1)
Coffee	✔️ GPL-3.0-or-later	Sequencers and utilities, some polyphonic
Comfortzone	✔️ GPL-3.0-or-later	Mainly a variety of oscillators, wavetable and granural sounds
Count Modula	❌ GPL-3.0-only	A lot of great tools for building/recreating synths in virtual.
cvly	✔️ GPL-3.0-or-later	Mostly polyphonic utilities.
CYC	✔️ MIT	Karplus-strong in a single module
dbRackModules	✔️ GPL-3.0-or-later	Polyphonic oscillators, scalers, randomizers, effects etc. Too many to cover. And all-pass filters!
Delexander	❌ GPL-3.0-only	A very unique tool for FM
Digital-Apothecary	✔️ GPL-3.0-or-later	An assortment of somewhat (mostly) unconventional modules with a unique theme - still working on dark theme
Dintree	✔️ GPL-3.0-or-later	Artwork license issues, author doesn't want others to use its artwork in any way
docb	✔️ GPL-3.0-or-later	Formula Editors, sequencers and unique sound generators
Edge	✔️ GPL-3.0-or-later	Oscillator, wavetable crusher and haas effect panner
Eightfold	✔️ GPL-3.0-or-later	Has an eight-voice algorithmic sequence generator
Formula by Frank Buss	✔️ BSD-2-Clause	Versatile tool for combining CVs using a freely editable formula
FrozenWasteland	❌ GPL-3.0-only	Excellent LFOs, and fantastic tools for microtonal music
fv1-emu	✔️ GPL-3.0-or-later	Spin Semi FV-1 DSP chip emulator
Geodesics	❌ GPL-3.0-only	Great for creating generative music
Holonic Systems	✔️ CC0-1.0	Contains Dumbwaiter, "an addressable 8 step sequencer and switch." ❌ Note: Connects to Holon.ist iOS app and communicates over OSC. Not particularly useful for Cardinal.
ILovePerlin	✔️ MIT	adaption of NauModular Perin Noise module
InfrasonicAudio	✔️ GPL-3.0-or-later	Warp Core - Dual-algorithm phase distortion and phase modulation oscillator
iggy.labs	✔️ GPL-3.0-or-later	Poly wavetable osc, selector and cellular automata sequencer
JA	✔️ GPL-3.0-or-later	Large collection of very small (2HP) utility modules. ❌ includes GPL-3.0-only code so possible license conflict
JLmod	✔️ GPL-3.0-or-later	Sequencer, poly "key split" and VCO
KarateSnoopy	✔️ MIT	2D grid sequencer
Kautenja PotatoChips	✔️ GPL-3.0-or-later	Exposes many classic soundchips to the modular workflow
KautenjaDSP-RackNES	✔️ GPL-3.0-or-later	NES emulator with CV
Kilpatrick-Toolbox	✔️ GPL-3.0-or-later	❌ Midi utilities and Quadraphonic decoders. Not particularly useful for Cardinal
KoralFX	✔️ BSD-3-Clause	Some utilities: clock/mixer/quantizer/preset-knobs/sequencer
Kosmodules-Free	✔️ Apache-2.0	Offset Scale Fold (Rack 1)
KRTPluginA	✔️ MIT	Many polyphonic audio and CV manipulators/manglers
LOGinstruments	✔️ BSD-3-Clause	Cable "labeler", noise gen, unpredictable signal generator, FFT visualizer
Mantra	✔️ GPL-3.0-or-later	Utilities and blanks (Rack 1)
Mental	✔️ BSD-3-Clause	Wide selection of CV and mixer utilities
MicMusic	✔️ MIT	Simple distortion and Adder
Milkrack	✔️ LGPL	The really cool Milkdrop Winamp oldschool visulisation in Rack
modular80	✔️ GPL-3.0-or-later	Two noise/random modules plus "official port" of MTM Radio Music sample player!
Mojo	✔️ CC0-1.0	Set of animal themed noise/oscillator/distortion modules
monome	❌ GPL-2	PRERELEASE modules of (some of) the Eurorack modules and control hardware manufactured by Monome
MyLittleTools	✔️ MIT	Modifies favorites and tag browser/handling? (Rack 1)
NocturnalEncoder	✔️ BSD-3-Clause	Decoders physical audio interfaces, like Expert Sleepers?
noobhour	✔️ BSD-3-Clause	Attenuators and attenuverters
NoraCodes	✔️ ISC	555 like oscillators (Rack 1)
NullPath	✔️ GPL-3.0-or-later	Small set of interesting modules with an emphasis on randomness
ODDSound MTS-ESP	✔️ 0BSD	❌ Modules for using microtonal tuning. Uses midi and needs a master plugin for quantization, so would need work and possibly not doable or re-implementation needed.
Ohmer	✔️ BSD-3-Clause	Clock generators/modulators, poly utilities, blanks
pfzzz	✔️ GPL-3.0-or-later	Function generator (Rack 1)
Plurm	✔️ GPL-3.0-or-later	S&H and Chording sequencer
QuantalAudio	✔️ GPL-3.0-or-later	VCO and daisy chainable mixer strips
ReTunesFree	✔️ GPL-3.0-or-later	Clock splitter, counters and patterns for four beats per bar (Rack 1)
RJModules	✔️ MIT	"complete" system of quirky experimental modules and utilities
RPJ	✔️ GPL-3.0-or-later	Polyphonic filters (Milkdrop visualiser with CV ins ****), oscillators and more
Sculpt-O-Sound	✔️ GPL-3.0-or-later	Two vocoders
Sequel Sequencers	✔️ GPL-3.0-or-later	3 row 8 or 16 step sequencer
Sha#Bang! Modules	❌ GPL-3.0-only	Nice collection of modules, including quantized probabilistic sequencers, percussion, LFO, etc
SignalFlux	✔️ GPL-3.0-or-later	Simple utilities
Sickozell	✔️ GPL-3.0-or-later	Great loopers, sampler, player, drums, ...
Skrylar	❌ ???	A great turing machine (in the eurorack sense) with all of its expanders - a cornerstone of my own patching technique.
SLM	✔️ GPL-3.0-or-later	Seems like a nice modulation/morphing tool, might need work to port to v2
Sparkette	✔️ GPL-3.0-or-later	Great RGB Matrix for visuals and other cool stuffs like Notes classifier
Squinky Labs	❌ GPL-3.0-only	Some of the best open-source oscillators and filters
Stalys	✔️ GPL-3.0-or-later	Mostly utilities based around logic and waveshaping
StochasticTelegraph	✔️ GPL-3.0-or-later	Modules with an emphasis on generative and self-regulating structure. Procedural programming module BASICally is very neat!
StochKit	✔️ GPL-3.0-or-later	Granular VCOs and a kind of delay
StudioSixPlusOne	✔️ GPL-3.0-or-later	Mostly polyphonic utilities, filters and sequencers
SynthKit	✔️ CC0-1.0	Logic utilities, clock dividers and sequencers
Seaside	✔️ MIT	Physical modeling of some indian instruments
T's Musical Tools	✔️ MIT	Contains a calendar module that generates signals based on date/time, plus utilities for working with polyphonic signals
TercerBrazo	✔️ GPL-3.0-or-later	Sega Genesis chip based synth (Rack 1)
TriggerFish-Elements	✔️ BSD-3-Clause	Noise and oscillators
Trowasoft	✔️ BSD-3-Clause	Multiwave osc module & Cool Multiscope module + SEQ and utilities in a pack. Fonts need license info and vetting.
Truly	✔️ BSD-3-Clause	Buttons
VCV-Recorder	✔️ GPL-3.0-or-later	Records stereo audio and video to a file
VenomModules	✔️ GPL-3.0-or-later	Large collection of utilities and expanders. Highlights are the Benjolin, Rhythm Explorer and VCO LAB modules.
WeldSplatter	✔️ GPL-3.0-or-later	plugin focusing on 12-tone music
wiqid-anomalies	✔️ GPL-3.0-or-later	Collection of chaotic attractor LFOs, utilities and Oscilloscope

Artwork Licenses

When * is used, it is meant as wildcard of all files, with potential exceptions mentioned afterwards.

Filename	License	Additional notes
Atelier/*	❌ Custom	Copyright © Pyer 2020, permission to use has been requested but not yet received
Dintree/*	❌ Custom	Requires permission for use, artwork license needs complete change
Dintree/fixedsys.ttf	❌ ???	Unlicensed font, has been solved in Dintree-Virtual#9