Serum - VST for FL Studio, Ableton Live, and many other VST supported DAWs. Heavily utilized in EDM.
FluidSynth - FluidSynth is a real-time software synthesizer based on the SoundFont 2 specifications and has...
Korg Legacy Collection - Korg Legacy Collection is a suite of VST instruments that acts as an audio plugin software for integrating synthesizers and effects units into your digital audio workstation.
Virtual MIDI Piano Keyboard - Virtual MIDI Piano Keyboard is a MIDI events generator and receiver.
SynthMaster One - Powerful, universal wavetable synth with an intuitive workflow.
EveryonePiano - Everyone Piano is the best free computer keyboard piano software, which supports downloading 3 types of music score formats like stave, right and left hand numbered musical notation and EOP file.