Last year Bethesda released Doom and Dishonored 2, both to critical acclaim. This year, Prey was released, and I think it's fair to say we will see more of all of those games at this year's E3.
Doom is the outlier here because the team at ID may have moved on and we won't see anything for a while -- however, I believe the success and popularity of the game will lead to some more DLC. This was hinted at by Doom creative director, Hugo Martin, who said they were considering a single-player expansion a few months ago. Needless to say, this expansion could have been in the making for a while now and Martin is simply keeping things under wraps. Any reason to go back to Doom for more single-player action would be welcomed by fans and receive a big pop at E3.
Dishonored 2 and Prey are guaranteed to get some screen time at this year's show. These are the two most recent releases for Bethesda, and neither has received any DLC thus far. So we could expect to see expansions for both games.
Quake Champions was revealed at last year's E3. The classic arena-based shooter returned with frantic action and 60 frames per second. The game has been announced as free-to-play if you want to use one character, and it's available for purchase to unlock the whole roster. The is an odd route for Bethesda to go down, but it seems the publisher wants to explore payment models. Quake Champions is a lock for this year's E3 -- and I would also expect a release date!