I have written fanfiction for Buffy the Vampire Slayer and Supernatural, as well as a Supernatural/Buffy/Angel crossover.
SUPERNATURAL/BUFFY THE VAMPIRE SLAYER/ANGEL CROSSOVER!
Death has come for Anya, Castiel and Illyria. Three creatures who have fought on the side of good, but have also done much evil. Now they wait for their final judgement, with only each other for companionship.
Friendshippy Castiel/Anya. Dean/Cas, Anya/Xander, Illyria/Wesley are talked about.
Rated R for some violence and brief sex, mostly this is a PG story.