A lot of people here seem to have a lot of other interests aside from Pokémon, so let's share! My fandoms include the Harry Potter universe, the DC universe, a tiny bit of Marvel (the X-men series in particular <3!), Disney, Studio Ghibli, Gravity Falls... I think that covers most of them, but I may be missing some! So, what are your fandoms?
I have waay too many fandoms. My favorites would have to be Steven Universe, SCPs, Undertale (depends), Earthbound, and OFF.
I've done myself a favour and stuck to two primary fandoms, with those being Pokémon and Miraculous Ladybug. I'm a fan of a ton of different anime but I like to avoid getting sucked into fandoms if possible
Undertale, off, how to train your Dragon, and gravity falls. those are some of my favorite fandoms. (Even though off isnt very popular anymore. Pepper steak for the win.)
As you can tell from my portrait, Persona is one of my favourite fandoms. Specifically Persona 4... I just find the story and characters so interesting, y'know? The music is awesome, the dungeons are really interesting, and the bosses are tough (not MS Saga tough, as those are unforgiving-tough, but they aren't jump-on-head-three-times-to-win easy, either). The AI doesn't screw you over, either. *glares at P3*
I probably am deepest in the Pokemn fandom, but I enjoy other things a lot, such as Legend of Zelda, Harry Potter, Doctor who (though I haven't watched much past eleven due to laziness) and the book series by Brandon Sanderson called Mistborn.
Pokémon's my main, and after that it's just kind of a mishmash of stuff I phase in an out of. I have my fingers dipped in a lot of different pies, some more than others. Zelda and Sonic are probably the big ones (though Sonic I actually fell out of until Mania, similar to how I didn't really get back into Zelda until Egoraptor's laughable OoT video and then the BotW announcement last year), but stuff like Star Fox, the Mana games, Etrian Odyssey, so on and so forth I'm also into. There's also non-game stuff like Star Wars and the like. It's too hard to narrow it down to just a couple, but maybe that's just my own problem. :V
The internet has mentally scarred me. Everytime i search something innocent, and totally normal, i find the unpleasant bits quite early.
I never really understood why there's so much hate/so many rivalries between certain fandoms. I just like pretty much everything. I could never get into Supernatural, which is weird because I usually like shows like that, but I like pretty much every other major fandom. Dying for some new Steven Universe episodes though! And Ladybug. And the new Doctor Who Christmas special with the first doctor in it, I'm so excited! It seems like all of my favorite series are on hiatus!
I stay out of fandoms for the most part, however I enjoy Earthbound, NiGHTS, Sonic (namely Chao), Pokémon, Digimon, Steven Universe, Monster Hunter, Undertale, Tattletail, Bendy and the Ink Machine, Legend of Zelda, Spyro, and Crash Bandicoot
*points meaningfully at profile* I'm a fangirl. This is kind of my job. I won't bore you with the list, but there's a lot of anime, mostly Death Note, AOT, and Black Butler (among many others), Harry Potter, Divergent, Maximum Ride, ect. I will not kill my fingers by typing the list. #MissingNo
Kirby is my other fandom right after Pokémon. I know it isn't a really big fandom, but I really do love what people do for the pink puffball. Plus I really do love Kirby a lot. His games are really good and the characters are well designed.
I have a bunch of other fandoms besides Pokémon. Zelda, UnderTale, Steven Universe, Adventure Time, just to name a few.