I don't think there will be a new Assassin's Creed this year but i wouldn't be surprised if they announce a considerable expansion for Origins, think The Witcher and Blood&Wine which would be awesome

Splinter Cell. I would love if they surprised us with a Red Steel 3 for Switch though

A new Rayman and Mario+Rabbids 2.

Splinter Cell and a new South Park game.

Rayman Legends sequel and a new TrackMania game.

I'm going into E3 with no expectations. I'll watch the ubisoft, EA, MS and sony shows. I'm getting increasingly annoyed with EA over their antics lately so they better have an impressive show.

From your list only AC Japan would interest me.

please give us a new Rayman game. Origins was amazing, as was Legends to a lighter degree.

Splinter Cell (already confirmed) and another title in collaboration with Nintendo, Davide Soliani (creative director for M+R) hinted that he'd like to make a Metroid game. Still I hope it'll be something radically different. Unless it's a Mario & Rayman RPG, that'd be allright, but make it as funny as possible

Given how The Division turned out to be a pretty good game after all was said and done, then i'm hoping to see a sequel.