It could be an evolution (or alternate evolution), a Mega Evolution, a form that could be changed, a regional variant, etc.

Example: I think Solrock should’ve had an Alolan form, and an evolution to go along with it.

As you know, Solrock is a Rock & Psychic, which is kind of cool, and it’s stats are the following:

HP: 70 Attack: 95
Defense: 85 Sp. Atk: 55 Sp. Def: 65 Speed: 70

95 attack wasn’t too back back in the day, but we’re in a new day & age, and it definitely need an upgrade.

Type:

Maybe it should’ve become an actual Sun Pokémon (either base form or evolution (leaning towards the latter)). The types that come to mind are Rock, Steel, Fire or Psychic. We know Solgaleo is already Psychic/Steel, so maybe Solrock would be Fire/Steel. Ability could be levitate or drought (or both lol). I think that would’ve been awesome.

Stats:

New stats could be something like:

HP: 80 Attack: 35
Defense: 80 Sp. Atk: 105
Sp. Def: 80 Speed: 60

It’s moves could be something like: Fire Move Steel Beam or Flash Cannon Solar Beam -Filler-

How about you?