Dear Moogle Claus,
Better late than never, I hope! This is my first year actively participating in the exchange (I pinch-hit last year), and I'm very excited!
Generally, I like good characterization, interesting relationships, slice-of-life/missing scenes, backstory, frontstory (that would be the opposite of backstory, right? stuff that happens after canon?), basically anything that acknowledges our characters as real people who have real lives aside from/outside of/before the plot. I'm not into stories whose problems could be solved by the characters taking five minutes to talk to each other like adults, or rooted in misunderstanding/wrong assumptions/pretending to be something they're not. (I don't like 85% of sitcoms for this reason.)
Beyond that, go with whatever rating the story demands - I'm really a big fan of turning the characters loose and letting them
dictate. Sex, violence, whatever you need to go for. The only squicky areas I have are non/dubcon, emotional or physical abuse, and humiliation.( Specifics on the prompts )