I write original fiction! Only that, in fact. @NikoSpear I get where you're coming from 'cause I'm also too shy to RP! Unless it's with friends but I'm usually playing canon characters so it doesn't count.
I have a lot of stories in progress but they're eternally stuck in the planning phrase, this is why I'm on this site, hoping to get my creativity flowing!
I mostly write urban fantasy; I have a story about a bookseller with a useless superpower, another one about the very unwilling vessel of Death, Fourth Rider of the Apocalypse, teaming up with Jesus, Judas, Lucifer and Gabriel to try and stop Judgement Day, another one about a talentless fortuneteller, and yet another one about the rightful ruler of the supernatural underworld having to fight her way to the throne.
I also have a noir crime story based on the urban legend of the Gloomy Sunday suicides, a sci-fi story about a programmer and her robot girlfriend, a historical fantasy about a Greek merman and a Celtic fisherman and a post-apocalyptic story where the characters are loosely based on classic Hammer and Universal monster movies. I told you I'm juggling a lot of them. Not that it matters 'cause I'm really not properly working on any of them in any measurable way.
I find it really hard to develop a plot apart from the core idea and actually get to the point where it has like a beginning, a middle and an end; even my most advanced storylines lack at least one of these. Sitting down to, y'know, actually write is out of the question. Talking to other people and sharing ideas helps an awful lot, though; I can think best if I'm explaining stuff to other people. So if anyone is any good at plotting, feel free to PM me! Can't promise instant replies 'cause I work full time and are usually brain dead by the time I get home, but I'd love to make some writer friends!