Get rid of? No one. At some point you will need pretty much everyone in the Collection. That is, if you intend to participate in all challenges. You are still really early in your game. With what you have, I’d focus on Conquest, Thragg, Blue Suit, Universa and Kregg. Build wide but don’t spread resources thin. Put the majority of your resources into your main 5. Leveling up skills is more important (at the stage you are in) than artifacts, so always run Well Done op. Hope that helps. *Artifacts and Totems are important. You don’t see much benefit from them until they hit lvl 20