Main Fandom above all others: Hard to say. As someone who can't commit to singular favorites, I'll just say Star Trek, Undertale, Metroid (haven't played the Prime Trilogy, so exclude what I don't know), Castlevania, Steven Universe, and Star Wars: Rebels.
Thoughts on Fan Characters: With Trek, I'm not familiar with any prominent ones. With Undertale, I generally stay away from AU's, although I do really like ' Glitchtale series and its OC's thus far. Don't delve into Metroid fan stuff. And Castlevania, Steven Universe, and Rebels, I'm also pretty lame. Besides, it's hard to ever come across OC's who aren't total Mary Sues and/or self-inserts. I mean, the franchises are good by themselves, y'know?
Thoughts on CanonxOC: Well, in my Phineas and Ferb days, I was surrounded by several instances of Canon-Fanfic pairings, and, to be honest, I never liked them then or now if they already had their own OTP's in-universe. So for example, to ship Phineas or Isabella with anyone but each other was heresy for me. Although I was pretty lenient with Ferb (by lenient, I mean being okay with Gretchen or Vanessa). Nowadays, I don't really come across (or seek out) fanfic-type stuff. Even in artwork.
Top Anime Series:
Well, since I don't really follow any but one, Fullmetal Alchemist: Brotherhood
Top Cartoon Series (not really in any order):
1. Steven Universe
2. Gravity Falls
3. Phineas and Ferb
4. My Little Pony: Friendship is Magic
5. Milo Murphy's Law
6. Star Wars: Rebels
7. Star vs. The Forces of Evil (casually)
8. Rick and Morty
Top Live Action (I don't watch a lot of live-action shows, to be honest...):
1. Star Trek: Deep Space Nine
2. Star Trek: Voyager
3. Star Trek: The Next Generation
4. Star Trek: Enterprise
5. Star Trek: The Original Series
(Animated Series doesn't make the list, haha...)
6. Does YouTube count...? If so, it's somewhere scattered throughout the list depending on who it is...
Top Movies (no particular order):
1. The Star Trek movies. Yes, all of them. There are clean ones and there are rough ones. But no offensive or "bad" ones, in my opinion. Emphasis on my opinion. I'm not being prescriptive. I'm being subjective. Star Trek V: The Final Frontier has to be the roughest-executed, in my opinion. Shame, considering its good elements.
2. The Star Wars movies. Yes, all of them. What I said above. Attack of the Clones, for all its awesome moments, has to be the weakest and roughest-executed in my opinion. Rogue One, Revenge of the Sith, and Return of the Jedi are my favorites thus far.
3. Terminator 2: Judgment Day
4. Rocky II, Rocky III, and Rocky IV
5. Animated Disney, as a whole. 2D, 3D, early, middle, or current ages, doesn't matter.
6. Batman (1989)
7. The Patriot
8. Various classic Godzilla movies
9. Jurassic Park (1 and 3)
Top Games (no particular order)
1. Star Trek Online
2. The Metroidvania CV titles (except for Circle of the Moon...and a love-hate with Harmony of Dissonance...)
3. The 2D Castlevania titles (haven't played Harmony of Despair) and non-Lords of Shadow trilogy 3D Castlevania titles (haven't played LoS games, and yes, I like the N64 titles)
4. 2D Metroid (Super Metroid, Metroid: Zero Mission, and Metroid: Fusion, in order; don't like the original NES game or Return of Samus; and AM2R: Return of Samus, a fan game, is FANTASTIC)
5. Animal Crossing: City Folk
6. Lego Star Wars: The Complete Saga
7. The Flash game "Super Mario Crossover 3"
8. Fan game "Mega Pony" (MLP x Mega Man 2)
9. Star Wars: Battlefront II (PS2, Xbox, PC)
10. The old Cartoon Network Flash game "Planetary Forces" (for the 2D Clone Wars; still here >>> lostdata.comuv.com/~games/clon… )
Other stuff that I like (in no particular order):
1. Milo Yiannopoulos. Long live The Dangerous Faggot! (Also, #GamerGate hero)
2. Steven Crowder. The strangest animal of all! (Fairest conservative I've known)
3. Sargon of Akkad. The witty British Classical Liberal whose brain overflows with knowledge and wisdom. (Also, #GamerGate hero)
4. Dave Rubin. The gay Classical Liberal who brought back conversation to politics. (Smart enough to leave TYT...)
5. Stefan Molyneux. Mr. "Not An Argument" will always make you ask the correct questions. (Philosophy)
6. YouTube Poops. Because YouTube is where the poop is!
7. Video game music. Yes, that means 8-bit, 16-bit, synth instrument, or orchestral. It's all fantastic.
8. Music from the Baroque, Classical, and Romantic Eras of music. Collectively called "Classical", for all you plebs.
9. The People's Republic of Kekistan. There is no god but Kek, and Pepe is his prophet. All Hail God Emperor Trump, and Shadilay!
10. Memes. They speak to the soul...and perfectly describe the human condition.
11. Vines. Same as memes.
12. Booze. I'm an adult, so suck it. I love dark beers, IPA's, dry red wines, and fruity cocktails.
13. Guns. Not as a fanatic, but as an average gun owner.
14. The Bible. Sorry, but I'm bound to its liberating ideologies. And no, faith and reason are not mutually-exclusive. Even science can become an irrational, corruptible dogma.
15. Science, especially biology and space science. Faith and reason are not mutually-exclusive.
16. The Angry Video Game Nerd. FFFFFFFFUUUUUUUUUUUUUU...!!!
17. Nostalgia Critic (sort of fading, though; liked his older stuff and early 2.0 stuff)
18. Jim-f*ckin'-Sterling, son. F*ck Konami. Oh, Ubisoft!
19. JonTron. The swoodest grommet on the internet. Officially red-pilled.
20. Caddicarus. No clever comment.
21. JackSepticEye. HAAAAAPPYYYYY WHEEEEELS!!!
22. Dr. Christina Hoff Sommers. The Factual Feminist herself, a former philosophy professor. Smart, classy, and nice.
23. Gavin McInnes. Quite the Canadian-American rebel.
Seen/Played it But Not a Fan at All:
1. Mean Girls...too much estrogen and mean-spiritedness.
2. First-person shooters. Cue MLG rage. Sorry, but I like third-person perspective. I'm only giving Metroid Prime a chance because it's Metroid.
3. A lot of mainstream stuff, to be honest. Modern comedy as a whole. Modern horror.
Anyone that sees this is tagged!