From Bulbapedia, the community-driven Pokémon encyclopedia.
This is a list of Pokémon that appear every regional Pokédex, listed in their National Pokédex order. All of the Pokémon that fit this description can only be from Generation I, due to the need to be in the Kanto Pokédex. This worldwide distribution is analogous to cosmopolitan distribution, the notion of a species that can be found anywhere on the planet.
There remain some Pokémon that have been included in every regional Pokédex since their release, such as Marill, but these Pokémon cannot be included in the main list. These Pokémon are listed below the main table.
While these Pokémon have appeared in every regional Pokédex, no Pokémon has appeared in every version of every regional Pokédex, as the Unova Pokédex of Pokémon Black and White did not include any Pokémon introduced in prior generations until it was expanded to become the New Unova Pokédex in Pokémon Black 2 and White 2. The Sinnoh Pokédex of Pokémon Diamond and Pearl, the Johto Pokédex of Pokémon Gold, Silver, and Crystal, and the Hoenn Pokédex of Pokémon Ruby, Sapphire, and Emerald were also expanded for their appearances in Pokémon Platinum, Pokémon HeartGold and SoulSilver, and Pokémon Omega Ruby and Alpha Sapphire, respectively.
List of Pokémon that appear in every regional Pokédex
These Pokémon appear in every regional Pokédex to date; this includes the Kanto, Johto, Hoenn, Sinnoh regional Pokédexes, New Unova Pokédex, and one of the three Kalos Pokédexes.
List of Pokémon that have appeared in every regional Pokédex since their debut
Since Generation II
These Generation II Pokémon appear in the Johto, Hoenn, Sinnoh, New Unova Pokédex, and Kalos regional Pokédexes, but not the Kanto Pokédex, as they did not appear in Generation I.
Since Generation III
These Generation III Pokémon appear in the Hoenn, Sinnoh, New Unova Pokédex and the Kalos regional Pokédexes. They are absent from the Kanto or Johto listings.
Since Generation IV
These Generation IV Pokémon appear in Sinnoh, New Unova Pokédex and the Kalos regional Pokédexes. Some of these Pokémon also appear in the updated Johto regional Pokédex and the updated Hoenn regional Pokédex.
Since Generation V
These Generation V Pokémon appeared in the Unova Pokédex and a Kalos Pokédex.