EA: Nothing much to do here since EA Play is already a part of GamePass. I guess extend that contract even further
Take Two: I'd give Take-Two whatever they asked for to get GTA VI onto game pass day one
Bandai: I'd get the Tales of series onto game pass
Square Enix: Most of the FF games have been in GamePass at one point or another. Outside of that, I don't see much point in doing any further business with Square Enix tbh.
Ubisoft: Assassins Creed games into game pass
Konami: Metal Gear Solid Games onto game pass
Sega: The Persona games have already been ported, so I would seek the SMT games to be ported next.
Capcom: Resident Evil
Warner Bros: Hogwarts Legacy
Embracer: idc
Koei Tecmo: Atelier games
Marvelous: Rune Factory games
NIS: The Legend of Heroes games
Paradox: idc
505: idc
Team 17: ???
Annapurna: Stray
Focus Entertainment: Nothing
Devolver: Cult of the lamb