Fan Fiction has many flavors and many kinds of stories. Which is to your taste? Well, let's see what is available. One thing... my pages are strictly Gen/Het, no slash. Sorry, folks.
These are all the genres I've located, and a lot of the definitions I reworked from a post by one of my list moms (Cat, take a bow) :
General: Fanfiction depicting a chain of events related to show's storyline. This may or may not include romantic involvement, depending on whether or not the show had the romantic involvement. Stories can be rated G to R in this category.
AU: Alternate Universe. An alternate universe is just what it sounds like... an alternate reality for a fan fiction story. It is where characters, places, themes are moved from their original setting and placed in a new world. (The Sentinel in Space series, Magnificent Seven ATF, Modern Day U.N.C.L.E. organization fics are all AU's.) It can also be used to describe what happens when an author changes things within the original settings (Jim and/or Blair getting married and having children, Buck finally marrying Inez, the Bobsey Twins finally growing up). If you want to borrow someone's AU as a basis for a fic, please get permission though, people get real touchy about it.
Het: Fanfiction depicting a chain of events that may move outside the show's original premise in the love interest area. Stories in this category will include a romantic involvement between male and female characters.
Stories can be rated G to NC-17 in this category.
Slash: Stories in this category will include a romantic involvment between two male characters or two female characters. Stories can be rated G to NC-17 in this category.
Other: Believe it or not, there is an other category. This is where Cat (and I agree with her, too) would stick fiction such as rape stories (which depict the rape graphically, rather than mention that it occured). They are not exactly het or slash because there is no romance or love involved. These stories are normally (or should be) NC-17 because of the graphic depiction. Most authors will give you a warning on this type of fiction.
Deathfic: Story in which a canon character is killed.
Crossover: Fanfiction which crosses two or more shows. For example: Quantum Leap / Time Trax brought elements from both shows together. Crossovers should focus equally on both/all casts.
Mary Sue: Original character who takes over the story. Usually a
representation of the author in the fic. Character is better at everything
than the canon characters are.
Canon: That which aired on the series or in the movie.
Fanon: That which was created by fans.
OFC: Original Female Character
OMC: Original Male Character
These are of course not precise.
G - Disney, or at least classic Disney
PG - Something I would not be embarassed watching with my parents. Or,
something which they might air on Fox Family
R - Adult situations, without necessarily being explicit
NC-17 - Adult situations, violence, non-consensuality (explicit or not)
(Yes, Cat, I loved your wonderful email describing this for your list, and I used it as a basis for my page's definitions. Why? Because you are a wonderful listmom who did a wonderful job of this.)