I'm going to be doing a series of posts soon on what if Ash was sponsored and/or trained by a Galarian Gym Leader, but for now, a list of suggested starters:
Milo:Applin
Nessa:Chewtle
Kabu:Sizzlepede
Bea:Clobbopus
Allister:Dreepy
Opal:Impidimp
Gordie:Rolycoly
Melony:Galarian Darumaka
Piers:Toxel
Raihan:Silicobra
The list may change.