There are over a thousand Pokemon thanks to Pokemon: Scarlet & Violet, and the franchise doesn't show signs of stopping. Despite this, a new type hasn't been added since 2013 - when Fairy-type was introduced to balance the power of Dragon- and Dark-types. Pokemon types determine which moves a Pokemon can learn, which moves do STAB damage, and are just generally representative of the Pokemon itself.
Among these many Pokemon are monotypes - Pokemon that are only one type. These can be great for Monotype Runs: self-imposed challenges where players limit themselves to one type, similar to a Gym Leader. Save for one special exception, this list only includes final-stage evolutions, as a testament to how well they represent their type. Many Pokemon gain an additional type when they evolve, but these have stayed true to themselves.
8 Eevee - Evolution Pokemon
The epitome of a Normal-type Pokemon, this Gen 1 favorite could not be ignored. Eevee is an adorable Pokemon that has eight different evolutions - known as Eeveelutions by the community. The reason Eevee makes the perfect Normal-type Pokemon is the potential it has to grow into so many types, though there are still several missing.
Eevee is so popular that it became the protagonist of its own game, alongside the series mascot Pikachu in Let's Go: Eevee. With that adorable fluffy mane, there's no wonder!
7 Sunflora - Sun Pokemon
Sunflora is an adorable Grass-type based on a sunflower. Evolving from Sunkern when exposed to a Sun Stone, Sunflora may not be the most powerful Grass-type, but it's certainly one of the most iconic. It even has a town dedicated to it in Pokemon Scarlet & Violet!
The happy-go-lucky Grass-type has made several appearances in the anime, specifically in Pokemon Explorers of Time, Darkness, and Sky. These games and the anime adaptation give a great insight into the personality of each Pokemon, and Sunflora is just as excitable and happy as its design suggests.
6 Banette - Marionette Pokemon
Introduced in Gen 3, Banette is an eerie Ghost-type that perfectly represents the spookier side of Pokemon. It's one of the few Pokemon with genuinely terrifying backstories - all of its Pokedex entries reference the fact that Banette is a Pokemon fueled by pure hatred. It's literally a doll that becomes a Pokemon when cast away by its owner and seeks vengeance against them for the abandonment.
It's just this that makes it the perfect Ghost-type Pokemon. The zip on its mouth keeps that life force contained within the doll, though Mega Banette becomes so powerful that it can't help but curse its trainer.
5 Gothitelle - Astral Body Pokemon
The Astral Body Pokemon Gothitelle is a fan favorite introduced in Pokemon Black & White. Based on the concept of astral projection and Gothic Lolita clothing, this pure Psychic-type makes the perfect, thematically consistent monotype Psychic Pokemon.
Gothitelle is the final evolution of Gothita and evolves from Gothorita at level 41. It's seen as the counterpart to Reuniclus, another pure Psychic-type three-stage evolution line with the same base stat total of 490, the same base experience and catch rates, with the exact same evolution levels for each stage.
4 Goodra - Dragon Pokemon
Goodra is such a strong monotype that its title is literally 'Dragon Pokemon'. A Dragon-type pseudo-legendary, Goodra is the final form of Goomy with a unique evolution gimmick. True to its slug-like appearance, Goodra only evolves from Sliggoo when it rains in the overworld - rain triggered by moves will not work.
This slug dragon has an impressive base stat total of 600, like all other pseudo-legendaries. In the Pokemon X & Y anime, Ash has a Goodra that evolves when the move Rain Dance is used - inaccurate to how it works in the games.
3 Mudsdale - Draft Horse Pokemon
Mudsdale is a pure Ground-type Pokemon introduced in Gen 7, based on a draft horse. The powerful Pokemon evolves from Mudbray at level 30. It's a great example of a Ground monotype Pokemon, as all of its Pokedex entries reference its strong affinity for mud. It makes sense, it's in the name!
Mudsdale makes a few major appearances in the anime, the first being under the ownership of Trainer Hapu. It helps her in her radish field with its incredible strength and later battles Team Skull Grunts.
2 Cinderace - Striker Pokemon
As the final evolution of Starter Pokemon Scorbunny, it's quite unusual that Cinderace didn't gain an additional type. It is a pure Fire-type based on a rabbit and a soccer player. Cinderace and its evolutionary line (Scorbunny and Raboot) were the only pure Fire-type Pokemon introduced in Pokemon Sword & Shield.
Cinderace is a great monotype with a consistent theming all around. Its signature move Pyro Ball combines the Pokemon's love of soccer and fire by having Cinderace kick a huge fireball at the opponent.
1 Palafin - Dolphin Pokemon
Palafin is a pure Water-type introduced in Pokemon Scarlet & Violet with a unique transformation gimmick that makes it super powerful. When switched out from the battle, the innocent-looking dolphin Pokemon activates its signature ability Zero to Hero, which increases its base stats to an incredible 650.
Given the bulk of Palafin's Hero Form, it should be a contender for Fighting-type, but it still remains a pure Water-type.