Ok, so... I'm not cool and sophisticated like all you alls, so my list quickly started sounding dumb.
...Uh... trees and uh... like... boobs.
Ok so, instead of trying to make a poetic, fancy list, I'm just gonna post some themes. ...These still won't make me look classy, but I tried. XD (K-CHAN I RIPPED OFF YOUR FORMAT)
Portals (now you're thinking with them!): Also, any and all ways of falling through one world and ending up in another. The vast majority of my early stories focus on this concept - mainly moving in the direction of from our world to another, which is a lot more fantastical and interesting than I tend to think of ours as.
Also, worlds merging, individuals being able to sense/experience multiple worlds at once, worlds existing behind and alongside our own, hidden to the uninitiated.
Nature: Also geology, ecology, meteorology, and since it fits better here than anywhere else, astronomy. The way the world looks just drives me crazy, especially in the wild places. Walking through a crazy forest or driving in the desert automatically makes my brain start putting characters into the landscape and invent crazy reasons for them to be there. So that's good! I really like utterly inhospitable and otherwise uninhabited places, and cultures that find crazy ways and reasons to live there anyway.
Landscapes like the sacred places in Utah and New Mexico - all those huge mesas and arches and red and orange stone and a sky too huge for words and big old canyons... Big nature things in general - huge trees, enormous rivers, caverns... things that dwarf people
Mythological beasties and persons: Yep yep, you know it. Dragons, unicorns, gryphons, minotaur, pixies, fauns, nymphs, the spirits in things like rocks and trees and clouds. I like kind of trying to put my own spin on the old things, or keeping the old things exactly the same and fitting them into a modern world, when it's possible. Which isn't even original but you know it's fun anywho.
Things that turn into other things: Like shifters! Especially when this happens to people who don't want/expect it to happen to them - that is all kinds of angsty fun.
Vampires and, to a slightly lesser degree, werewolves YES I DON'T CARE I LIKE THEM ANYWAY.
The concept of going evil and coming back: I first fell in love with this in... I don't even remember what it was. Maybe a Nimh sequel, it was some animated thing with mice and one went FREAKIN' CRAZY and tried to kill everything but then he came back and turned good and I always get this awesome feeling from that kind of dynamic, which is really more than a big morbid and cruel because then the character has to look at all the horror and harm she/he's caused and THAT'S no fun. For them. :p
DRUGS: Things that alter minds, addictions, hallucinations, trances, gritty back alley deals, compromises to get that next hit. Conspiracies of big corporations secretly distributing drugs, drugs coming in from other worlds, drugs that do more than just trip you out. Oh, and stoners. I think they make great heroes. ;p
SPACE: THE FINAL FRONTEER OF... YOUR FACE. Ok no. But seriously... space. I have a Sci-Fi called Trax that I'd really really like to finish someday, I just love the genre and all the crazy cool things you can do with it. Bizarre planets, awesome cultures, crazy monsters... SPACE SHIPS, tech, STARS... I like both the reaslitic SF where it's stuff that could concievably happen and the more out there kind with like... space whales. :p IT'S ALL AWESOME.
And I guess now that I've gone there I'll have to mention Fantasy: High, urban, mythological, whatever. I especially like smashing together high fantasy and urban fantasy and seeing what happens, and I REALLY like making myth stuff into urban fantasy. I have a background project about Native American mythology which was really amazingly fun to work on, I'd like to get back to that too. But I also definitely will go back to my first love and the reason I want to be an author in the first place, which is high fantasy. Your typical running around swinging a sword dragons and princesses thing. But my way. :p
Zombies: Does this need any explanation? Needs moar zombie survival stories, imo.
Love: Or rather, the lack thereof. Love stories that don't work out, one-sided love, love that ruins the story instead of giving it its little blaze of glory at the end. I KNOW RIGHT, what a sadist!
Epic journeys At the end of a story, I tend to want my character to have come a loooong way. By the same token, I tend to try to stay away from the whole, at the beginning of the story she is a farmgirl, at the end of the story she is the QUEEN OF EVERYTHING. It's hard to avoid that probably, but I wouldn't know because I never finish anything. XD
A little list of things
marbles and shiny stones and pebbles
ruins and abandoned places
bags and kits
knives and swords
secret passages and mazes
the ocean, for that matter
things with defined edges - here is the jungle, BAM here is an abyss
Weird animals like giraffes and platypi
clothing specifically for extreme weather
AND THAT... IS ABOUT IT.