When it comes to third-party news, I'm not a massive fan of Resident Evil but I'll be interested to see if that gets announced either through Capcom (are they doing an event?) or at Nintendo's Direct. Timed exclusive Resident Evil would be a big announcement for Nintendo to make themselves.
EA confirming they've got their shit together and that Switch is getting Mass Effect Trilogy would be noice. I can wait for news on Triangle Strategy because I'm yet to even try the initial demo, but I am desperate to see more of Dragon Quest III 2D-HD. Confirmation that's late 2021 would be amazeballs, so I'm tempering myself and thinking 2022 for that (which is probably way likelier). Ubisoft need to get their shit together in an entirely different way, but if Soliani and his team have done another Nintendo game, then Kingdom Battle 2 announced at Ubi's event would be good to see.
I'd like to see something come out of blue, whether from Nintendo themselves, or in the shape of a third-party making a major game with Switch as the lead platform. It should be the case that the swathe of Dragon Quest titles are using Switch as their lead platforms, but who knows. But another, less predictable franchise or new IP coming from another third-party would be good.