From Bulbapedia, the community-driven Pokémon encyclopedia.
The list of Pokémon obtained in Pokémon Diamond by Vixen Windstorm is an extensive feature of the Pokémon Windstorm has obtained in the game, including a runthrough of his party, under the Pokémon Trainer ID Steven. Each Pokémon listed is one that is presently owned in the game, not one that appears in the Pokédex but has since evolved and can no longer be found, physically.
Windstorm has yet to überize Mewtwo, as evident by its moves. However, once Charizard reaches level 100 Mewtwo will be next.
Windstorm stores his Pokémon in Bebe's PC, dedicating each box to 30 Pokémon, and placing them in order of their National Dex number. For example, Bulbasaur is #001, and so would appear in the first spot in Box 1; Hippowdon is #450, and so would appear in the thirtieth spot in Box 15. The following is a list of all Pokémon Windstorm currently owns in Pokémon Diamond, both his party and boxed Pokémon: