So far, there are Eevee evolutions for Dark, Electric, Fairy, Fire, Grass, Ice, Psychic, and Water types. The latest Eevee evolution was Fairy-type Sylveon, introduced in Pokemon X and Y all the way back in 2013. It's been nearly a decade since a new Eevee evolution has been added to the Pokemon lore, so it will be interesting to see if the upcoming Pokemon Scarlet and Violet give fans a new one.
While fans wait on official word from Nintendo about a potential new Eevee evolution in Pokemon Scarlet and Violet, some fans have taken matters into their own hands, creating new Eevee evolutions based the unrepresented types. Reddit user Novablazar is one such fan, creating an impressive Ground-type version of Eevee that they've named Dusteon.
Other Pokemon fan artists have created Eevee evolutions over the years, covering the other types that remain unrepresented in the games. For example, one fan recently shared their concept of what a Poison-type Eevee evolution could look like. The jury is still out on whether or not Pokemon Scarlet and Violet will be adding a new Eevee evolution at all, but one has to wonder if it will be a Ground or Poison-type like these fan artists have imagined, or if it will be something else.
It's also possible Game Freak and Nintendo may introduce more than one new Eevee evolution in Pokemon Scarlet and Violet. Leafeon and Glaceon were both introduced to the Pokemon franchise as part of Pokemon Diamond and Pearl, while Espeon and Umbreon were both added in Pokemon Gold and Silver. Sylveon is the only time a new Eevee evolution has been introduced by itself, in fact.
As it stands, Game Freak and Nintendo have revealed very little about any new Pokemon coming in Pokemon Scarlet and Violet. Fans know what the Pokemon Scarlet and Violet starter Pokemon look like, but that's about it at the time of this writing. With the new games set to launch at some point later this year, though, more information should come to light in the months ahead.