Grookey is the Grass-type starter of Pokémon Sword & Shield, while Scorbunny is the Fire-type starter, and Sobble is the Water-type starter. The player will most likely be able to choose from any of these three Pokémon when beginning their adventure in the Galar region.
Though we were only given a brief glimpse at the Galar starter Pokémon, we were also given a short demonstration of their abilities and personalities. There has yet to be any reveal of the second or third evolutions for the Galar starters, but we're going to speculate on the types that they may become when they fully evolve.
Scorbunny was shown to possess an incredibly fast running speed during its debut, as we see it running up vertical surfaces and leaving a fiery trail in its wake.
There was a period of time when three of the Fire-type starter Pokémon all evolved into Fire/Fighting-type creatures, with Torchic, Chimchar, and Tepig all following this pattern.
The impressive physical attributes of Scorbunny suggest that it may become a Fire/Fighting-type Pokémon when it achieves its final form. Rabbits are famous for having powerful back legs that they use to kick, so we could see Scorabbit's final evolution using fiery kicks like Ken from Street Fighter.
Sobble has already started to win fans on social media thanks to its dour demeanor, despite the fact that it didn't do much in the trailer.
There is a moment in the Pokémon Direct when Sobble appears out of the water while invisible before taking on his regular form and running up a tree.
The fact that Sobble possesses the ability to become invisible suggests that it may evolve into a Water/Ghost-type Pokémon when it achieves its final form. The only other Water/Ghost-type Pokémon that have appeared in the series are Frillish and Jellicent, which would give Sobble's final evolution a rare typing.
Grookey isn't the first Grass-type monkey in the Pokémon series, as Pansage (and its evolution, Simisage) has already covered similar ground.
It might seem as if Grookey doesn't do much in the Pokémon Sword & Shield trailer outside of banging a stick and climbing a wall, but there is something subtle that happens that may hint at its final evolution.
Scorbunny scorches the ground when it first arrives and Sobble puts out the flame. The reason why Grookey bangs the stick on the ground is that it is somehow involved with its ability to restore plant life, as the grass that was destroyed by Scorbunny comes back to life due to Grookey's influence.
Grookey's ability to restore plants suggests that it may evolve into a Grass/Fairy-type Pokémon, possibly with some kind of druidic influence, which would make sense when you consider that the Galar region is based on the United Kingdom.