Mantis

"Ma'am, we need you to control him." Tony Stark flew swiftly to Mantis's side. In the future they had seen, Mantis had controlled Thanos for a brief time. If Star-Lord had not learned of Gamora's death and beaten the mind-hypnotized Thanos until he woke up, they would have removed Thanos's Infinity Gauntlet long ago. The Guardians of the Galaxy might have seemed like a bunch of comic relief characters. But every one of them was highly capable. There was no need to mention Star-Lord, Peter Quill.