Get this free retro effect patch from Frank Pole.
Download all abandoned Darkware plugins from Jack Dark here. These 32 Bit plugins might need something like Jbridge to run but are still worth it.
Here are 3 examples:
Bedroom Producers Blog releases BPB Saturator, a freeware tube and tape saturation effect in VST, VST3, AU, and AAX plugin formats for digital audio workstations on Windows 10 and macOS.
Texture is an easy to use granular reverb with pitch shifting and mid/side mode. Texture can transform any sound into an ambient soundscape, or add that drone vibe to your tracks. This plugin was inspired by the techniques used in the soundtrack and sound design of the award-winning indie game The Swapper.
You can choose your own price (also free is possible) for 2 interesting FX plugins from Freakshow Industries. You decide.