Hmm... Okay I'll try my best to help you with this... :)

Lovestory = Is the same as romance except for the fact that lovestory probably has a lot more sweet scenes and it usually revolves on characters having ages of 25 or less. Romance allows ages 26 and higher.

Korean = Fanfics that revolve in the country of Korea.

Oneshot = Fanfics that have only one chapter.

You = Fanfics where you are the main character and events revolve around you.

= Fanfics that have scenes between guys and girls.

= Fanfics that have guy x guy scenes.

Schoollife = fanfics that revolve around school events and students.

friendship = fanfics that portray the ups and downs of friendship, usually have tests of trust as .

tragedy = fanfics that have events showing chaos or destruction of the characters' lives. The tragedy can be physical, mental, social, or emotional.

supernatural = fics that portray ghosts, spirits and other stuff that are extraordinary.

mystery = fics where the charcters go through solving mental problems and make analyses as to a certain life event, uncovering secrets as the story progresses.

mature = fanfics having strictly content... May have violence, , , etc. in it, or a combination of all.

marriedlife = fics portraying the life of married person/people.

well, i randomly selected some genres. Do you have any more genres you want to know? ^_^
I hope I could be of help. :)

some also write horror too

there's also action, suspense which is like a thriller, supernatural and paranormal which deal with topics like ghosts angels vampires werewolves stuff like that. there's also fantasy which is like Harry Potter or Lord of the Rings.

angst: depressing, sad
one-shot: a short fic, only lasting a chapter or so
au: stands for alternate universe
slash: boy on boy love
femmeslash: girl on girl love
:
crack: a silly fic, meant to be funny
drabble: an experimental fic; usually short

hm. that's all i can think of.