I'm a fan of:

Straight Shota

Huge Proportions (breasts, cocks, asses)

Harem/multi/threesome

Femdom (only in straight shota fics)

Maledom

Adultery (only when the main protagonist is the one stealing the lover or wife of someone else instead of being the one whose lover is stolen)

Basically, I love fics about one guy getting lucky with multiple women, especially if the guy is hung as a horse and the women have breasts and asses so big they barely fit the clothes they're wearing.

My fic challenges/requests (If you're not a fan of the above elements, you may wanna avoid these.):

Avatar - The Last Airbender: Adult Version: http://www2.adult-fanfiction.org/forum/topic/56627-avatar-the-last-airbender-adult-version-challenge/

Ben 10: Adult Version: http://www2.adult-fanfiction.org/forum/topic/57481-ben-10-adult-version-challenge/

Ben 10/DC Comics crossover: http://www2.adult-fanfiction.org/forum/topic/44619-ben-10dc-comics-crossover-challenge/

Ben 10/Mortal Kombat Crossover: http://www2.adult-fanfiction.org/forum/topic/56057-ben-10mortal-kombat-crossover-challenge/

Danny's Harem (Danny Phantom Fic Challenge): http://www2.adult-fanfiction.org/forum/topic/62206-dannys-harem-danny-phantom-fic-challenge/

Disney's Big Hero 6/Marvel crossover challenge: http://www2.adult-fanfiction.org/forum/topic/60304-disneys-big-hero-6marvel-crossover-challenge/

Harry Potter and his big-breasted harem: http://www2.adult-fanfiction.org/forum/topic/55610-harry-potter-and-his-big-breasted-harem-challenge/

Harry Potter and the Witch of the Black Rose (Harry Potter/Tarot crossover): http://www2.adult-fanfiction.org/forum/topic/65782-harry-potter-and-the-witch-of-the-black-rose-harry-pottertarot-crossover/

Hiccup's Huge Dragon: http://www2.adult-fanfiction.org/forum/topic/55681-hiccups-huge-dragon-httyddragons-riders-of-berk-fic-challenge/

Hiccup the Overlord (HTTYD/Disney/Overlord crossover fanfic challenge): http://www2.adult-fanfiction.org/forum/topic/60162-hiccup-the-overlord-httyddisneyoverlord-crossover-fanfic-challenge/

How To Train Your Dragon 1 & 2: Adult Version Challenge: http://www2.adult-fanfiction.org/forum/topic/58024-how-to-train-your-dragon-1-2-adult-version-challenge/

Jurassic Park Straight Shota/Femdom Fic: http://www2.adult-fanfiction.org/forum/topic/55244-jurassic-park-straight-shotafemdom-fic-request/

Matt the Hero (Batman Beyond Challenge): http://www2.adult-fanfiction.org/forum/topic/67003-matt-the-hero-batman-beyond-challenge/

Resident Evil: The VR Experience: http://www2.adult-fanfiction.org/forum/topic/66790-resident-evil-the-vr-experience/

Robin, the Boy('s) Wonder(ful cock): http://www2.adult-fanfiction.org/forum/topic/55996-robin-the-boys-wonderful-cock-fanfic-challenge/

Teenage Mutant Ninja Turtles 2012: Adult Version Challenge: http://www2.adult-fanfiction.org/forum/topic/59249-teenage-mutant-ninja-turtles-2012-adult-version-challenge/

Tinkerbell Harem Fic Challenges: http://www2.adult-fanfiction.org/forum/topic/52750-tinkerbell-harem-fic-challenges/

The boy and the Haunted House: http://www2.adult-fanfiction.org/forum/topic/53969-the-boy-and-the-haunted-house-challenge/

The Frozen sisters and the hung mountain man: http://www2.adult-fanfiction.org/forum/topic/56554-the-frozen-sisters-and-the-hung-mountain-man-frozen-fanfic-challenge/

The Spellbook (Beast Boy/Harem fic challenge): http://www2.adult-fanfiction.org/forum/topic/62983-the-spellbook-beast-boyharem-fic-challenge/?view=findpost&p=393062

Straight Shota Story Ideas: http://www2.adult-fanfiction.org/forum/topic/63224-straight-shota-story-ideas/?view=findpost&p=393772