I really doubt that the Zelda development team will EVER announce a new IP. Especially when Breath of the Wild 2 is in development (and likely other Zelda titles). I honestly cannot think of any circumstances in which they have developed other titles. Feel free to correct me if I am wrong.
As for my predictions in no particular order:
Metroid Prime Trilogy HD.
Link's Awakening HD recap/new details.
Town update (I am guessing that it will be delayed until Q1 2020).
Luigi's Mansion 3 recap/new details.
A decent/good third party port gets announced and releases around November 2019 (similar to Bethesda's announcement for Doom 2016).
Pokemon Sword & Shield - recap + more Galar forms and a couple new Pokemon reveals.
A sizzle reel for already released/announced games (Spyro, Witcher III etc.).
I am guessing that there will be one more direct this year in November.
I also think that there will be a mini-direct for Mario Maker 2. It will show some new features, perhaps a new style that has been alluded to?
A mini-direct/presentation for Smash Ultimate. It will show off Banjo-Kazooie and version 5.0
I personally do not think Grand Theft Auto V will be announced for the Switch. I think that if they were going to do it, it would have released by now. This has nothing to do with the Switch's hardware (the game ran on Xbox 360 & PS3). I just think that like EA, Rockstar/Take-Two isn't interested in the Switch.
Games and debauchery.