I guess it will be a subsection of version exclusives and it only just started in generation 7 but feels like this is going to be a thing from now and like how most gens have like the pikaclone(albeit with much more design freedom
Gen 7: Lycanroc's evolutions are version locked in SM, Lycanroc Dusk comes with by far the best ability and special encoutner method alongside being a "traits of both" pokemon . Future games have them just being time based
Gen 8:Applin has the items needed to evolve being version locked. SV had both apples being found regardless of version with the DLC introducing Dipplin which can evolve further than the others with Hydrapple.
Gen 9: Armor pieces needed can only be forged based on version
by theguyinyourwall