-Peru's osu! community is pretty bad. Sure, the international osu! community can be just as toxic in general but I feel like country-specific ones are going to have a more concentrated toxicity...
-On that note I would also like to state particular "indie game" communities. Games that got super popular thanks to YouTube or other social media generally tend to attract the little kids, which was the unfortunate fate of UNDERTALE. FNAF also fits this as well.
-Why do FPS and MMORPG games have the worst people lol i don't like the latter now mostly because i don't want to associate myself with them
-I'm seeing Splatoon and Pokemon among the usual replies. While I can't say for sure about Splatoon (though I have heard of horror stories from there), I will have to agree Pokemon fans can sometimes go borderline apeshit. When the leaks of Let's Go! started popping up everyone basically hated on it because it was too similar to Pokemon Go and started dreading the series going that direction. The announcement of a main game coming 2019 didn't ease the "pain" at all.
-And finally, leeching from the competitve scene of Pokemon is most fighting games, Super Smash Bros. in particular. I only learned to DI properly so that I could drag matches on and entertain myself while I'm at it, because the competitive scene there is horrible and any attempt to make friends there is useless.
There are more like Roblox and Minecraft and perhaps some others but it would eventually amount to me just hating everyone and everything in general lol