Serum - VST for FL Studio, Ableton Live, and many other VST supported DAWs. Heavily utilized in EDM.
Unstable by De La Mancha - Unstable by De La Mancha is a pitch modulation effect tool packed with inspiration and creativity.
Surge XT - Open-source subtractive-hybrid synthesizer formerly sold commercially as Vember Audio Surge.
Dumpster Fire by Freakshow Industries - Dumpster Fire by Freakshow Industries is a multi-dimensional virtual effect audio plugin that allows you to shape the sound of fire in all its forms.
Vital - Vital is a spectral warping wavetable synthesizer with drag'n'drop modulation workflow and animated preview of the synth's inner workings where needed. Comes with many modulation sources (including audio-rate), MPE support and FX chain.
SketchCassette - SketchCassette is a plugin that simulates the sound effect of cheap tape, lo-fi effects, sounds of music cassettes, and 8-bit music.