least toxic anime fandom

Thinking better, I never had any issues with CGDCT guys. It's a relaxing genre, so the biggest part of the group is nice.

I might be a bit biased cause it's one of my favorites, but No Game No Life fans are generally pretty chill. Sometimes they ask "where's No Game No Life season 2" on the announcements of new seasons of completely unrelated shows (admittedly, this happens quite a lot), but they don't often do anything more toxic than that, which is more than I can say for most anime fandoms.

the Ecchi fandom and Hentai fandom.

Y'all better stop spreading your sweet lies about how cool and chill slice-of-life/CGDCT community is. It is toxic enough.
The least toxic fandom is obviously hentai fandom.
The second one is GAR (or MMDMT - Manly Men Doing Manly Things) fandom.
Oh, and how could I forget about retro fans.

Slice of Life and Cute Girls Doing Cute Things.

Doraemon and Detective Conan fan are clean af.

people who like performing arts anime, they're just here to see some cool music and dance

Slice of Life/CGDCT/Hentai/Ecchi fans are chill af. The last pick is mostly due to how Ecchi is becoming little common nowadays

Oh freak how can I forget about Gintama fandom... everybody can agree that they are the most chill from the usual Shounen fandom

Gintama and Kaguya-sama come to mind

This is facts . The most annoying and toxic animefans i have met are Sols

Kinmoza

we all just say ayaya ayaya ayaya

Never read anything negative about / in Natsume Yuujinchou in that small fandom.

Candy Candy, I think. Because it is not so popular.

Coming from my own perspective as being a MAL user now for well over a year, I have noticed in general no particular fandom is toxic in this community. If you are actually paying attention, it's more so noticing it's the same type of vocal individual users on MAL that make fandom toxic or not. Either by obvious fake accounts where you got users make their 1st and sometimes only post toxic, or outright have a user that skirt the forum rules by purposely creating discussions specifically meant to agitate certain groups within the active community.

I would have to say the "least" toxic fandom on MAL are simply those that just don't even participate in any of the forum discussions in the 1st place.