FluidSynth - FluidSynth is a real-time software synthesizer based on the SoundFont 2 specifications and has...
VCV Rack - A cross-platform modular synthesizer.
ZynAddSubFX - ZynAddSubFX is an open source software synthesizer for Linux, Mac OS X and Microsoft Windows.
Pure Data - Pd (aka Pure Data) is a real-time graphical programming environment for audio, video, and graphical...
VirtualMIDISynth - VirtualMIDISynth is a software MIDI synthesizer implemented as a Windows multimedia user driver...
miRack - Eurorack-style modular synthesizer for iOS.