yoshimi - Yoshimi is a software synthesizer for Linux based on the 2.4.
Qsynth - Qsynth is a simple Qt4 application wrapper for the ...
FluidSynth - FluidSynth is a real-time software synthesizer based on the SoundFont 2 specifications and has...
Zebralette - u-he makes creative software synthesizers and effects.
ZynAddSubFX - ZynAddSubFX is an open source software synthesizer for Linux, Mac OS X and Microsoft Windows.
Surge XT - Open-source subtractive-hybrid synthesizer formerly sold commercially as Vember Audio Surge.