Eevee can evolve into eight different Pokémon species in the Pokémon games. These forms are Vaporeon, Jolteon, Flareon, Espeon, Umbreon, Leafeon, Glaceon, and Sylveon.
The first three evolutions appeared in the original games: Vaporeon is Water-type, Jolteon is Electric-type, and Flareon is Fire-type. Later generations added evolutions associated with friendship, time of day, locations, evolutionary stones, and other requirements.
Eevee’s branching evolution line is unusual because one base species can become several different species rather than following only one fixed path. The games use different conditions to determine the result, so players cannot always choose an evolution simply by leveling up.
Eevee is also unusual because it has remained important across games, animation, merchandise, and special editions. Its many possible forms are sometimes called “Eeveelutions,” a fan term that later became accepted in official Pokémon usage. Pikachu is not one of Eevee’s evolutions, despite both being prominent mascot Pokémon.