Favorite OC-Only fanfics?

Have you ever read a fanfic comprised entirely/mostly of OC's? Like a Harry Potter fanfic that focuses on an original group of Hogwarts students, or a Star Trek fic that focuses on an original starship crew? I want you to send me your favorite examples of those kinda fanfics, ones where you really liked the OC's. I'm Fine with any tag and any fandom, send me anything.