- RubyInstaller2 uses MSYS2 to build Ruby for Windows in CI and as build environment for gems with C extensions.
- Gaphor uses MSYS2 for its Windows releases and for CI
- Git for Windows is based on MSYS2
- Quod Libet uses MSYS2 for its Windows build and for CI
- HDL/MINGW-packages uses MSYS2 for building and testing open source Electronic Design Automation (EDA) tools.
- ghdl/ghdl uses MSYS2 for building, packaging and testing GHDL.
- ghdl/setup-ghdl-ci uses setup-msys2 for users to run GHDL on GitHub Actions' Windows environments.
- ghdl/extended-tests uses setup-msys2 and setup-ghdl-ci for testing third-party projects with GHDL on GitHub Actions' Windows environments.
- gtkwave/gtkwave uses MSYS2 for building and packaging GTKWave.
- steveicarus/iverilog uses MSYS2 for building, packaging and testing Icarus Verilog.
- trabucayre/openFPGALoader uses MSYS2 for building, packaging and testing openFPGALoader.
- azonenberg/scopehal-apps uses MSYS2 for building libscopehal, glscopeclient and other client applications for libscopehal.
- Serial-Studio/Serial-Studio uses MSYS2 for building and testing Serial Studio.
- VUnit/vunit uses MSYS2 for testing VUnit.
- ghdl/ghdl uses MSYS2 for building, packaging and testing GHDL.
- ImPPG uses MSYS2 for its Windows releases.
- Inkscape uses MSYS2 for its Windows releases and for CI (Documentation)
- KeePassXC uses MSYS2 for building and running KeePassXC password manager.
- Media-autobuild_suite uses MSYS2 for automatically building FFmpeg and other media related tools
- Network UPS Tools uses MSYS2/MinGW for "semi-native" builds of NUT for Windows (cross-builds on Linux+MinGW are also possible).
- Nuwen's MinGW Build uses MSYS2 to build the files.
- OpenModelica uses MSYS2 for building the OpenModelica tools and compiling the generated simulation code on Windows.
- Paperwork uses MSYS2 for its Windows releases and for CI (Documentation)
- The R Project build system rtools40 is based on MSYS2 icw/ a custom repository of mingw packages (all statically linked).
- Spatial Model Editor uses MSYS2 for its Windows releases and for CI
- UrusStudio Installer uses MSYS2 for building and running Urus Studio IDE and URUS System.
- Webots uses MSYS2 to build Webots on Windows and for CI.
- Xournal++ uses MSYS2 for its Windows releases and for CI (Documentation).
- Neovim uses MSYS2 for its Windows building and running (Documentation).
- darktable uses MSYS2 for its Windows releases and for CI (Documentation)
- Mesh2HRTF uses MSYS2 for its Windows NumCalc binaries (Documentation).
- PVSnesLib uses MSYS2 to build ROMs on Windows
- Crown Engine uses MSYS2 for its Windows releases and for CI.
Feel free to add your project to this list!