Urban Fantasy, High Fantasy, Epic Quest, Sci-Fi, Time Travel and World Hopping, Steampunk, Action/Adventure, Modern Drama, Mystery, Slice of Life, Romance, and many more.
Yes, me and my friends played ten minute costumes and I ended up being The Undertaker. I regret not posting our picture in the costume contest since it was a group of a cyclist, a half assed pirate, Elis from Left for Dead, and OC named MoonMoon.
Fantasy is my #1; I will give almost anything a chance if it has strong fantasy elements. Post apocalyptic, superhero, alternate history, science fantasy, some supernatural, romance, and a few fandoms (especially Game of Thrones) are also likely to catch my eye.
Speaking of going out trick-or-treating after the generally acceptable age, the last time I did it was when I was four years ago, when I was 21. I didn't even pretend to be younger, nor did I do a good costume. I just grabbed a mask, put it on over plain clothes, and then went out and raked in the candy. I went out at about 10 PM and ended up getting quite a few people who'd dump all their candy into my bag because they were headed to bed and such.
Screw moral or ethical concerns, free candy is always great.