Stole from everyone and their mother:
Creature Fics: Well, Castiel is technically a creature, right? Angel and everything. So yes. I also love a good ALLSCALMTM vampire fic. Werewolves? Not so much.
Animagus: I haven't really run into this too much. I guess it's fine if it's a crack fic, but if they're having sex? No. I get really creeped out by all those prompts for fics with J2 and the dog.
Mpreg: I used to be really squicked by this, but I've read some really good ones recently. I'm looking at you,
arctic-grey. As long as the connection between the would-be parents is strong, I'm all on board. Now, egg!fics, I'm less certain off....
Slave: I've actually read a really good slave!fic in the SPN fandom, but I think I only like it because Dean and Cas aren't of the same species. And Dean treated Cas with complete respect. I get really turned off with people using one another, so if slave!fic turns into that, I'm gone.
BDSM, S&M: Yes. As long as it's not too extreme, but a little playing never (severely) hurt anyone.
Age difference: This is a big dealbreaker with me. If they're both old enough to make the decision, it's fine; but 40 year old teacher with impressionable, wanting-to-please and naive 15 year old student? No.
Blood-Play: I would normally say no way in hell, but then I read
this and it worked.
Under-age (chan): If they're both underage but not too young (I'm partial to think that 16 and up is okay), then it's just peachy. I can't get into kid!slash. It really squicks me.
Cross-dressing/Gender bender: Yes yes yes yes. I really like pretty boys in panties. Think of Brendon Urie's ass in silky lace! And for Dean, it's canon!
Dubious-consent: Matters how dubious. If it borders on more than just a "well....maybe not" then I'm gone.
Non-con: No.
Incest: No. I have never understood the big popularity with this. I won't go as far as some people who say that people who read/write incest must not have siblings, but really... this just turns me off so fast. And I'm glad I came into SPN fandom after Castiel came in, because Sam/Dean makes me :(
Threesome/more-some/gang-bang: YES! As long as my OTP is super strong, I'm happy. (Also voyeurism. Mmmmmm, yes please.)
Death: If it's done well. And makes me weep.
Water-sports/scat: NO.
Crossovers: Yes, yes, a million times yes.
Unhappy/wide open endings: I love open endings. Who would have thought, right? And an unhappy ending can be good once in a while. :D
Infidelity: Normally I have a big problem with infidelity. I do love THROAM, but in everything else, it's a deal breaker. You guys know I'm a hopeless romantic!
Self-harming/Attempted suicide: I have rarely found this to work in any fic I've read. The only suicide fic that works, in my opinion, is
this Rimming: Yes. Again, something that fandom really opened my eyes on. Damn, fandom loves rimming!
Felching: EIther/Or
Fisting: Not my thing. It's a little too intense.
Addictions/Disorders: I hate fics with drug addiction. I've seen what it can do to people irl, and it's not something I want to read about for entertainment.
Torture/Violence: No.
Toys: Yes! (though one time I read a fic where I think the author forgot about the position of all the toys, because people can't talk intelligibly with a gag in their mouths, of give oral sex with it in)
Uniforms: Less of uniforms, more of aus. I love a good au.
Double penetration: In het, yes. Slash? One guy taking two dicks at the same time? No.
Anal (het, gay and/or lesbian): Um..... Slash fan here. *raises hand* Hi.
Deep-throating: Yes, as long as the person receiving doesn't just use their partner.
Boot worship, foot fetish: Not my thing.
Chains, shackles, collars, handcuffs, and other means to restrain a character: Totally. Consensual bondage = YES.
Blindfolds: Sure.
Certain places such as dungeons, prison cells, interrogation room, offices (add your own if you have one I didn't mention): I may have an office!kink. What? It can be hot. Read
this for proof.
Mind games/mind fuck (you know, that nice psychological approach to bend a character to one's will and/or break them): No. I've read far too many manipulative!Ryan in far too many bad fics for this to work for me.
Food play/sploshing: Eh.
Gore/guro: Never.
Fight for dominance: A million times yes!
Breath play/asphyxiation: I have to be in the mood, but yes. It's more about the trust between the characters, for me.
Hair-pulling/biting/scratching/bruising: Love it!
Gun play/knife play/wand play (knife play does not have to include cutting someone, and you can add some other inanimate object to the list, if you have one!): No. I get that there needs to be trust, but in most cases, it just turns me off.
Drugs or intoxication: Warm, lazy pot happy high with panic, sure :) Coke binge? No.
Language kink (accents etc.): ? Enochian? Yes. When Cas can't help but slip up. And dirty talk x infinity.
Squick fics (aka fics that are meant to squick the hell out of you): I don't understand the logic of this.
Have to get married!: Yes! Bonding fics, too!
Soul- (life-, heart-, force-, marriage-, wizard-, etc.) bonds: MY FAVORITE THING EVER. THIS IS EPIC LOVE!
Hurt/comfort: It's okay.
Kid!fic: Yes. I love good parents!
Time travel: So amazing! Especially when characters encounter other versions of themselves/people they know.
AUs: So much fun. This is the reason that fandoms last so long. We can write about anything!
Amnesia: I wrote one that I really like and have read a couple of good ones, but this can very easily go bad.
Undercover!gay/Have to pretend to be a couple: Like if Dean and Cas were investigating a gay club? Or NRWC era stage gay? YES!
Redeemed!evil character: I don't really think that there is enough space in fics for this to happen. To be believable you need like 3 seasons in a tv show. Like Spike *sigh*