Magus would probably be Thanos' opposing rival for obtaining the Infinity Gauntlet but Grim Reaper would be effective as a servant of Thanos but I still wish Red Skull would make a comeback since he was transported to the farthest reaches of the galaxy.

I think having both Adam Warlock and Magus in the same movie when introducing both characters would be a bit much. I definitely wanna see Nova and I wish Victoria of Spartax but after the absolute garbage twist of Ego being Star-lord's father, I doubt the Spartax Empire will play as significant of a role as it should.

@kundelar: Gunn could imply that J'son has fallen out of favor with the Spartax empire and the crown went to Victoria. J'son and his Slaughter Lords could be a rival Ravager Group. I will admit they kinda watered down Ego' s power. For example, when Nebula was shooting at Gamora, couldn't Ego feel the wave of blasts hitting his surface or for that matter wouldn't he have eyes everywhere. Ego would have found out that Gamora discovered his children's mass grave site.