A lot of these aren’t exactly “niche”, but afaik none of them exist on lemmy yet

Edit: for some reason, a bunch of these that actually do exist weren’t showing up in search unless I specifically searched for “!community@instance”. I’ve gone back through and added links to them here.

r/actuallesbians
r/anarchychess [email protected]
r/anime_irl
r/animemes [email protected]
r/beyblade
r/bropill
r/conlangs
r/datahoarder [email protected]
r/ddlc
r/egg_irl [email protected]
r/femboymemes
r/forbiddensnacks [email protected]
r/gravityfalls
r/heraldry
r/heraldrycirclejerk
r/infinitytrain
r/katawashoujo
r/leopardsatemyface
r/logh
r/lycorisrecoil
r/madeinabyss
r/madokamagica
r/math [email protected]
r/mathmemes
r/mbtimemes
r/mechanicalkeyboards [email protected]
r/mushokutensei
r/musictheory
r/nails
r/nextfuckinglevel
r/oshinoko [email protected]
r/philosophy [email protected] [email protected]
r/photoshopbattles
r/playstupidgames
r/pokemongo
r/portal [email protected]
r/princessesofpower
r/programmerhumor [email protected]
r/shitduolingosays
r/shitpostcrusaders
r/stardustcrusaders
r/stevenuniverse
r/swordartonline [email protected]
r/talesfromtechsupport [email protected]
r/the10thdentist
r/thinkpad [email protected]
r/tokipona [email protected]
r/touchfluffytail
r/traaaaaaannnnnnnnnns [email protected]
r/transadorable
r/transprogrammer
r/transhumanism [email protected]
r/transtrans
r/visualnovels [email protected] [email protected]
r/wholesomeyuri
r/yurimemes