Something like HL3 is not paying to be shown there. Geoff would do it for free just because reputation.Why would valve waste money on a slot at the show? They have no need to advertise there, just put a banner on steam and be done with it. Realistically it doesn't even need to get to that point, just create the store page and some bot will scrub it in half a second.
This will be something related with Fromsoft, possibly that game that shall not be named but I wouldn't hold my breath.
The second thing will either be nintendo hardware, extremely unlikely, or some PS sequel like last of us, uncharted or god of war.