During the February 2025 Pokemon Presents show, Nintendo revealed the three starter Pokemon players can choose from in Pokemon Legends Z-A: Chikorita, Tepig, and Totodile.
So far, that’s all the information we have on the three starters. Pokemon Legends Arceus had alternate Hisuin final evolutions for its starters, each with a different typing compared to their original forms. It hasn’t been confirmed whether the starters in Pokemon Legends Z-A will have alternate final evolutions as well.
However, Nintendo confirmed that Mega Evolutions will be making a return, so it’s possible that the starters could receive those. There’s been a precendent set with Mega Evolutions where some get new typing, such as Mega Ampharos being Electric/Dragon instead of pure Electric type and Pinsir becoming a Bug/Flying type when it Mega Evolves instead of staying pure Bug.
Source: Gamespot Meet The Three Starters In Pokemon Legends Z-A