https://www.mindwerks.net/projects/wildmidi/
https://en.wikipedia.org/wiki/Software_synthesizer
https://knowyourtheory.com/
https://yoshimi.github.io/
https://surge-synthesizer.github.io/
https://tytel.org/helm/
https://amsynth.github.io/
https://awesomeopensource.com/project/FluidSynth/fluidsynth
http://timidity.sourceforge.net/#info
https://www.laborejo.org/documentation/patroneo/english.html