Microsoft have announced that all games shown during the Xbox Games Showcase will support Xbox Game Pass.
Head of Xbox Phil Spencer announced (at 44:06) that all games will be available through their subscription or free-to-play options.
These titles include Halo Infinite, State of Decay 3, Forza Motorsport, Everwild, Tell Me Why – Chapter One, Ori and the Will of the Wisps, The Outer Worlds, Grounded, S.T.A.L.K.E.R. 2, Avowed, As Dusk Falls, Destiny 2, Warhammer 40,000: Darktide, Tetris Effect: Connected, Fable, Phantasy Star Online 2: New Genesis, The Gunk, The Medium, CrossfireX, Watch Dogs: Legion, Senua’s Saga: Hellblade II, and Psychonauts 2.
You can find the full list of games available through Xbox Game Pass here.