Whereas the mainline entries often have starters harder to come by in the wild, this isn’t the case with the “Go All Out” event — meaning choosing Grookey, Scorbunny, or Sobble in Pokémon ...

Though it's important to note that this is a branching research quest so, at quest step one, you'll be asked to pick between three different paths - Adventure with Grookey, Scorbunny or Sobble.

Pokemon GO Galar Calling Special Research is ... Make your choice among Grookey, Scorbunny, and Sobble. The partner you choose will also impact the Postcard Book background for the season.