From Bulbapedia, the community-driven Pokémon encyclopedia.
This is a list of Pokémon by their color according to the Pokédex. While the actual colors of the Pokémon species can vary, the color listed in the Pokédex is usually the color most apparent or covering each Pokémon's body. No orange category exists; Pokémon that are primarily orange are listed as red or brown. Pokémon with multiple forms, such as Wormadam and Shellos, are categorized into their most common form's color. For unknown reason, Game Freak puts a few of the Pokemon into a color group that is different than their most apparent color. Some examples including Druddigon (whose most apparent color is blue, yet is put into the red category), Aerodactyl (whose most apparent color is gray, yet is put into the purple category), Mawile (also mostly gray, but is put into the black category), Chimchar (mostly red but is put into brown category), Bronzor, Bronzong, Golett, and Golurk (does not have any green on their body and are mostly blue, yet they are in the green category), and Mantine (mostly blue, but is in purple category).
Red
Blue
Green
Yellow
Purple
Pink
Brown
Black
Gray
White