This is a list of Pokémon species. They apparently are mostly based on real creatures such as animals and plants; others are based on supernatural beings such as gods, dragons and ghosts; there are also diverse exceptions, for example some based on rocks, pollution, CGI polygons and compasses.
Language overview 
Each species is originally named in Japanese, specifically in the katakana script; notably, there are also ニドラン♀, ニドラン♂, ポリゴン２ and ポリゴンＺ, each including an exceptional, non-katakana character: ♀, ♂, 2 or Z.
There are also official romanized names for each Pokémon; for instance, カメックス is officially also named in Japanese as Kamex. These official romanized names apparently are usually, but not always, chosen with the English pronunciation in mind, such as ニャース being romanized as Nyarth.
Subsequently, Pokémon names are adapted into English, German and French, also by simply romanizing the Japanese version (e.g., Chicorita became Chikorita), or by changing the name entirely (e.g., Lucky became Chansey). In the Italian and the Spanish official versions of the franchise, Pokémon species are named after the English version without further adaptations.
Usually, Pokémon names in all languages roughly point to biological characteristics or other contexts of each creature. For instance, there is Cocoon, the Japanese name for Kakuna, a Pokémon whose appearance is of a cocoon; and, in English, there is Koffing, named after coughing.
Unofficial species 
In addition to the official Pokémon, there are unofficial ones.
List of fake Pokémon 
Some names of common species of Pokémon became well-known despite not being official.
- Mewthree (“a supposed member of the family of Mew and Mewtwo”)
- Pikablu (“Marill”)
- Porygon3 (“a supposed evolution of Porygon2”) This officially ended up to be Porygon-Z.
List of Glitches 
Some peculiar Pokémon species may appear in video games as a result of glitches.
- Bad Egg (“an egg that hatches into another egg”)
- Invisible Shiny Bulbasaur (“a shiny Pokémon without sprite but with the cry of a Bulbasaur”)
- MissingNo. (“the result of accessing a data point not programmed with a Pokémon”)
List of official species 
Note: The list above hasn't been updated to include the 156 new Pokémon introduced after Arceus.