Looks like there are going to be a ton of surprises in Guardians of the Galaxy Vol. 2. That is unless you don’t read the spoilers. i09 had the story.
Near the end of the movie, new characters played by Ving Rhames and Michelle Yeoh appear. The credits (as well as James Gunn at the press conference) confirm they play Charlie-27 and Aleta Ogord, two ravager leaders in the film. Exactly why they appear is STILL too big of a spoiler to share, but in one of the five end-credits scenes, they meet up with Stakar, played by Sylvester Stallone, and two other aliens: Krugarr and Mainframe. The five characters vow to get back together and steal some shit.
Aleta Ogord first appears in Defenders #29
Charlie-27 first appears with the rest of the original Guardians in Marvel Superheroes #18
Krugarr first appears in Guardians of the Galaxy Annual #1
Mainframe first appears in A-Next #1