Okay, I'm writing a letter as fast as I can.
Dear crossovering writer,
If you matched one of these requests, we already have at least three things we love in common: two fandoms and crossover fic! And I will love your fic. I read crossovers even if I only know one fandom well and have a passing acquaintance with the other.
What else do you need to know about me? I'm primarily a gen person. I don't like reading hurt/comfort fic, or stories that contain graphic descriptions of rape or torture. Stories that humiliate and embarrass the characters will make me feel unhappy and uncomfortable too. Please, be kind to the characters! It's a rare writer who can keep me reading through a lengthy sex scene, or even a short one unless it's pertinent to the plot.
What do I like? I love poetry and prose. I like stories that take underdeveloped bits from canon and enlarge them, make them come to life, and show us something new about the characters and their world. I love a well-plotted mystery or adventure. I like alternative universes and stories about time travel and future fic. You already know I love crossovers! I like snappy dialogue and banter. I love post-eps and missing scenes. I like stories about friendship. I like stories about love.
I'm an optimist. I know life is hard. Bad things do happen to good people. However, I like reading stories about how people cope with adversity; how they get through the hard times, and come out on the other side, transformed in some way by those experiences.
Elementary: My favorite character is Joan Watson. I watch the show for the banter and the friendship. I love mysteries but I think the plots on this show are pretty predictable. Like most fans, I'm there for the characters.
Crossover elements: Crimes and the people who solve them. (Luckily, the rest of these series are jam-packed with those elements.) Doctors who leave medicine to become crime-solving detectives and hang out with eccentric, driven men with difficult family backgrounds. Evil corporations who want to rule the world. Bees. Evil scientists. Kidnapped children. Characters who would do anything to save the person they love most in the world.
Fringe. My favorite character is Walter Bishop but I love every version of Olivia in every universe. Overall, my favorite season is three, my least favorite season is five.
Crossover elements: Weird science. Mutants. Crimes and the people who solve them. Evil corporations who want to rule the world. Human experimentation. Kidnapped children. Saving the planet and/or universe from certain annihilation. CANON ALTERNATE UNIVERSES! TIME TRAVEL! Evil scientists. Parapsychology. Characters who would do anything to save the person they love most in the world.
Orphan Black: I started watching the show this year. It's a lot of fun, and also kind of crazy, so definitely my kind of show. And there are so many great female characters! Maslany is an amazing actor. I think all of the clones are wonderful characters, as is Felix, and Mrs. M. I love the monitors and the evil scientists.
Crossover elements: CLONES! Mutants. Weird science. Crimes and the people who solve them. Kidnapped children. Human experimentation. Evil corporations who want to rule the world. The clone monitors. Major Characters dying of a genetically engineered illness. Sexy assassins. Evil scientists. Characters who would do anything to save the person they love most in the world.
Stargate SG-1: This is probably the hardest show to write crossover fic for--but I've done it, so if we matched on this, take heart! My favorite character is Sam Carter. I love team-centered fanfic. I love the whole concept of sending teams through the Stargate to explore other planets in faraway galaxies.
Crossover elements: ALIENS! Crimes and the people who solve them. Human experimentation. Canon ALTERNATIVE UNIVERSES! CLONES! Weird science. Saving the planet from certain annihilation several times a season. A canon TV show within a show based on the Stargate program! Time travel. Body swapping. Sex Pollen. Evil scientists. You name the fic trope, the Stargate writers put it into their canon.
Yes, there are characters who would do anything to save the person and/or persons they love most in the world.
Warehouse 13: I love the characters, especially Claudia, and the wacky things that the artifacts do. I shipped Myka and H.G. Wells. Sigh.
Crossover elements: </i> Crimes and the people who solve them. Weird science. Time Travel. Human experimentation. Parapsychology. Magic. Body Swapping. A Major Character dying of cancer. And all those artifacts--you know some of them must be extra-terrestrial in origin. It just stands to reason. Characters who would do anything, etc.
The X-Files: I love Mulder and Scully, but especially Scully.
Crossover elements: ALL of the above, from aliens to time travel, plus a canon movie within a TV show made about the X-Files characters and their cases and a canon crossover with Cops. And yes, two characters who would each do anything to save
Here's my advice: write whatever you like! Enjoy yourself! If I can think of an actual prompt, I'll probably have to use it myself. (No, not really. I already know what I'm going to write.)
The main thing I want is for you to have fun with this assignment. Vague though they are, I hope the suggestions in this letter can help you to do that.
I like shows that can combine humor with more serious elements, so at least they all have that in common.