Mine'll be the "slightly obscure gag that I'm not sure people get" genre. But there's never an option for that on the sites I use...
I tend to stick mainly to humour related to films, music and sometimes technology. Although I am planning to start a story some time soon that's mystery/thriller (and also film-related). But I'll wait to see how that goes before I start using words like "proficient"! I'm still piecing together the ideas for it, I don't like starting things if I'm not certain where it's going so it might be a while.
I do have some other ideas I'd like to work on that probably come under speculative fiction which I think could be very interesting. I should hurry up with those ideas before they become either non-fiction or alternative history!
Genres I think I would struggle with: I think similar to the OP, writing romance I'd find difficult.