VCV Rack (macOS, Windows and Linux)
VCV Rack is a virtual modular synthesizer for MacOS, Windows, and Linux. It has an extensive library of modules created by third parties, many of which are free and open source.
All of the monome modules have open source firmware, which have been generously extended by members of the community. These firmwares were ported by @Dewb to the VCV environment with feature parity. You can connect physical grid and arc, or use virtual versions which are included in the collection.
The original documentation for the physical modules all apply to the virtual versions as well.
Note that serialosc needs to be installed to connect to physical grids and arcs.