Nintendo to announce Switch's successor this FY, Switch 1 Direct coming in June

[Tober]

Let's look at last first parties on previous systems. It might give us a clue what to expect this year.

NES: Wario Woods
SNES: Kirby's Dreamland3 (1997)
N64: Dr. Mario 64 (2001)
GameCube: LoZ Twillight Princess (2006)
Wii: Kirby Dream Collection (2012)
Wii U: LoZ Breath of the Wild

With no cross gen Zelda game expected, my bet is on Kirby (new game, remaster or collection)