M51 Galaxy is a free VST Synthesizer Instrument Plugin.
CZynthia is a free VST synth with Two Phase Distortion Oscillator sections each offering two sets of 8 waveforms.
String Synthesizer is a free VST instrument emulation (no samples here!) of those string synthesizers of the late 70’s made famous by ARP and Solina. It features a full ADSR envelope generator, a small effect section with a phaser, a delay and of course the ‘ensemble’ effect.