Yeah Xfer records do a really good free bunch. Same as Voxengo.
TAL do some excellent freebies too! - https://tal-software.com/
def seconding voxengo and tal, SPAN (voxengo) and reverb-II (tal) are fantastic
cmt bitcrusher's a nice distortion plugin as well, and if you're looking for some chiptune sounds magical8bitplug and chip32 are really good (chip32 especially if you're wanting an additive chip synth)!
i'd also recommend izotope's vinyl but they discontinued it, sadly. you can probably find it if you hunt for it tho.