Types & Definitions of Genres:

Action/Adventure:  A genre of stories featuring a plot with a fair amount of physical action. Yes, stories with gangsters/assassins/mafias are considered action stories. Adventure stories tend to be mainly plot-driven in nature, but may also contain mystery or suspense or romance.

Angst: A genre which the stories usually have heavy and sometimes depressing themes, and have the characters suffering emotionally (and sometimes physically) in some way. Relationship break up, character death, hurt and comfort are all forms of angst stories. Such stories may also be used to evoke such emotions in readers.

AU/Alternate Universe:  A story of which there is a deliberate change in plot, setting or character in a particular universe. Stories that fall in this category are usually what-ifs, where possibilities arising from different circumstances or character decisions are explored.

Comedy: Stories in which contains a few scenes that consists of logical jokes, intended to make readers laugh. Such stories may also have a few scenes in which a character says or does something stupid or laughable.

Crack: Stories in which completely ridiculous, unbelievable or insane things occur, often without reasonable explanation but great enjoyment. Such stories are generally written shamelessly and with no excuse beyond the desire to have fun. Such stories are almost always hilarious.

Dark:  Stories in which either the content, or, the characters themselves are written darker than their usual counterparts. Can range from morally ambiguous to evil. Such characters may also have psychopathic/sociopathic behaviour. "Dark" refers to plots which introduce elements such as death, violence, betrayal or loss. "Dark" fan fiction builds upon preexisting emotional attachments that readers have with the characters for dramatic effect. Stories often carry high ratings due to disturbing subject matter.

Drama:  Stories with plots that contain many unexpected events or plot twists.

Fantasy: Stories in which contains a plot that is of one's imagination. Such stories are usually unlikely to happen in real life. In a way, such stories are make-believe. Such stories usually revolves around magic or mythology beings.

Fluff: Stories in which there is no angst or, often, any real plot either. Fluff stories tend to be short and sweet, with little to no depth, but often quite comforting to read.

Genderbender:  Stories in which a character of one gender undergoes some kind of gender change at some point throughout or before the story. It can be temporary or irreversible. It can be serious, or often, quite humorous.

Historical:  A story set in a recognizable period of history. As well as telling the stories of ordinary people’s lives, historical fiction may involve political or social events of the time. Such stories may also contain romance. E.g. of historical times include Josean Dynasty.

Horror:  Stories with contents that are intended to evoke emotions such as fear, shock or disgustt in readers.

MPreg: Stories in which a male character is capable of conceiving or carrying a child in his body.

Mystery: Stories in which one or more elements remain unknown or unexplained until the end of the story. The modern mystery story contains elements of the serious novel: a convincing account of a character’s struggle with various physical and psychological obstacles in an effort to achieve his goal, good characterization and sound motivation.

Psychological: Stories that emphasize the mental and emotional aspects of its characters, focusing on motivations and mental activities rather than on exterior events. Such stories usually involve characters with disorders.

Romance: Such stories contain plots in which the love relationship between a man and a woman ades the plot. The story is often told from the viewpoint of the girl, who meets a man, falls in love with him, encounters a conflict that hinders their relationship, then resolves the conflict.

Romance Comedy:  Stories in which contains a plot with a mixture of humor and romance.

Sci-Fi/Science Fiction: Science fiction can be defined as stories involving elements of science and technology as a basis for conflict, or as the setting for a story. Science fiction writers make their own rules for future settings, but the field requires consistency.

Slice of Life:  Stories which contain realistic representations of everyday experience. Basically, such stories speak of utter reality.

Supernatural:  Stories that involve characters with ablities that are unexplainable by science or nature. Such stories usually involve werewolves, vampires or psychic abilities. Such stories also involve powers.

Thriller: Stories that are intended to arouse feelings of excitement or suspense. Works in this genre are highly sensational, usually focusing on illegal activities etc. A thriller is often a detective story in which the forces of good are pitted against the forces of evil in a kill-or-be-killed situation.

With that said, here are some things for you to note:

1. Comedy and Crack are two very different genres.

2. Sci-Fi and Fantasy are completely different from one another.

3. Angst + Comedy fanfics? I still wonder how people write such fanfics. If your fanfic is an angst-based one in overall but contains a few jokes here and there, then tag it as Angst. If your fanfic is a comedy-based one in overall but contains a few sad scenes here and there, then tag it as Comedy.

4. Fluff + Angst fanfics? No, please don't.

5. Only tag your fanfic as Drama if there are many unexpected events or plot twists.

Need help identifying the genre for your fanfic? Feel free to ask me :)