iZotope Vinyl - iZotope Vinyl is a plugin that gives you the tools to cut, shuffle and alter your audio content to give it that lo-fi vinyl sound.
Serum - VST for FL Studio, Ableton Live, and many other VST supported DAWs. Heavily utilized in EDM.
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.
Surge XT - Open-source subtractive-hybrid synthesizer formerly sold commercially as Vember Audio Surge.
SketchCassette - SketchCassette is a plugin that simulates the sound effect of cheap tape, lo-fi effects, sounds of music cassettes, and 8-bit music.
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.