>>40471511I have a feeling Ash will go with Sobble as his main starter, as Sobble typically follows the emotionally expressive to badass vibe that he usually gets for starters. (Sobble is confirmed through Affleck to evolve into a spy Pokemon, and spies are cool. Grookey evolves into a big gorilla with a wooden drum, and I can't see that going for Ash.)
Ash will also most likely have Corviknight as well, unless it goes to Go or Koharu specifically. Ash typically gets the regional bird, and a datamine of a phone app shows Corviknight is the final stage of Galar's regional bird. (The one time Ash didn't get the regional bird was also the only region where Ash got a bird starter Pokemon. There is no bird starter this time around, so Ash should catch Corviknight's first stage and evolve it all the way to its last one.) Also, the fact that Corviknight itself has a Gigantamax might indicate that Ash's possible Corviknight will also be one that Gigantamaxes, as Ash has recently caught gimmick or unique Pokemon.
Ash rarely gets the regional bug Pokemon, but he usually gets one as a caterpillar. He might get Galar's regional bug. (Almost always somebody on the main cast gets a regional bug ever since Gen 3.)
Ash has always received at least one Fire-type in every region he goes to, but then again he didn't have a Grass-type in Kalos, or a Water-type in Alola, so he might not have a Fire-type in Galar.