You can actually pick any character/couple you want! Since I've got General Series and no one else has made a claim, they're all up for grabs. Straight from the fanfic100 rules:
If I pick general, can I use characters the have been picked by other people? ♥ Yes. If you pick general series, you can use every character that passed through the series. If you picked a pairing, you must use both of those characters, but you may include any other characters with them. Same applies if you picked one character. For example (thanks [info]becky_h), if you have X-Men general series, you can write about any pairings of any X-Men, Scott/Jean, Erik/Xavier, Emma/Angel, etc, no matter if someone has picked Scott or Emma or Xavier. If you have Scott, you can write about Scott with any other X-Man, Scott/Jean, Scott/Warren, Scott/Bobby, etc, no matter if someone has picked Jean or Warren or Bobby. If you picked Scott/Warren, you have to include both Scott and Warren in your fics, no matter if someone else picked Scott or Warren. I hope that clears it up.
Re: fanfic100
If I pick general, can I use characters the have been picked by other people?
♥ Yes. If you pick general series, you can use every character that passed through the series. If you picked a pairing, you must use both of those characters, but you may include any other characters with them. Same applies if you picked one character. For example (thanks [info]becky_h), if you have X-Men general series, you can write about any pairings of any X-Men, Scott/Jean, Erik/Xavier, Emma/Angel, etc, no matter if someone has picked Scott or Emma or Xavier. If you have Scott, you can write about Scott with any other X-Man, Scott/Jean, Scott/Warren, Scott/Bobby, etc, no matter if someone has picked Jean or Warren or Bobby. If you picked Scott/Warren, you have to include both Scott and Warren in your fics, no matter if someone else picked Scott or Warren. I hope that clears it up.