Bend's new game, said to be an open-world survival/horror game according to Shinobi, is a possibility. Media Molecule could also, in theory, announce their main project but that would seem strange when they have Tearaway announced and needing promotion.
Outside of those two, Guerrilla, Capcom, and indies, I don't see too much potential for new IP. Polyphony is working on Gran Turismo, Studio Japan probably wouldn't announce something at a western event like this, Santa Monica is almost certainly working on God of War, San Diego is churning out another MLB game, and it's probably too early to hear anything from Cambridge, Sucker Punch, or Quantic Dream.