Regional variants

Alolan Form
In Pokémon Sun and Moon, if a Pokémon evolves from a species that does not have an Alolan Form to one that does, such as Cubone, it will always evolve into its Alolan Form and cannot evolve into its normal form. In Pokémon Ultra Sun and Ultra Moon, the Pokémon will evolve into its Alolan Form while in Alola itself, but can also evolve into its normal form while in Ultra Space.

While Pokémon: Let's Go, Pikachu! and Let's Go, Eevee! take place in Kanto, players can import Alolan Forms from Pokémon GO or receive them from in-game trades. Alolan Forms of Pokémon present in the Galar Pokédex are unavailable by normal means in Pokémon Sword and Shield and can be obtained by transferring them from Generation VII. Alolan forms of Pokémon included in The Isle of Armor expansion pass are available as rewards for finding hidden Alolan Diglett on the Isle of Armor. An Alolan Meowth even makes a cameo appearance in the NPCPokémon Camp on Route 7.

A total of eighteen Alolan Forms were introduced in Generation VII, all of which are for Pokémon introduced in Generation I.

Galarian Form
Unlike Alolan Forms, there are Galarian Forms of Pokémon from beyond Generation I, and several Galarian Forms have an evolution that their regular form does not.

Currently, a total of nineteen Galarian Forms have been introduced in Generation VIII.

benlian forms
they are like galarian forms but in the region of benlia.

there is currently 1 confirmed in the generation 9 dex.