From Bulbapedia, the community-driven Pokémon encyclopedia.
This is a list of Pokémon that appear every regional Broswer, listed in their National Pokédex order. As of Pokémon Ranger: Guardian Signs, this includes the Fiore Regional Browser, the Almia Regional Browser and the Oblivia Regional Browser. 69 of the 386 Pokémon in existence at the time of the release of Fiore's Browser are in this list.
List of Pokémon that appear in every regional Browser