Though Deadpool as a character may be wacky enough as it is, there's no doubt that the X-men comic universe has loads of different and interesting characters that have yet to make an appearance in a film. Besides Cable and Domino, writers Paul Wernick and Rhet Reese have told fans to keep an eye out for more mutants and villains from the comic to make their way to Deadpool 2.
In an interview with Latino-Review for promoting Life, Wernick and Reese revealed:
"Yeah, Cable and Domino grabbed the headlines on Deadpool. But there are definitely some more obscure characters that people know or that real diehards know that will be in there just by virtue of we need a new villain, and we need some new good guys to compliment [Deadpool], but it is growing. Of course, it will be all about the lunacy that is Deadpool himself."
An "obscure" character that made an appearance in the first movie was Negasonic Teenage Warhead (Brianna Hildebrand), but the sad thing was, her movie powers had no resemblance with her abilities in the comics. The writers just really wanted the character for the crazy name. Hopefully they could stick closer to the powers of whoever they decide to introduce next. I have a feeling Marrow could possibly be brought back. She was hinted at in the first movie.
No specific release date has been announced for Deadpool 2, but it's targeted for an early 2018 release.