Several repositories offer "God Saves" or completed Pokédex files for download:
With all 649 Pokémon sitting in your PC, the Unova region becomes your ultimate playground. Whether you are aiming to dominate the PWT or casually stroll through the story with a team of mythicals, a complete save file breathes incredible new life into this Nintendo DS masterpiece. If you need help setting this up, please let me know: pokemon white 2 save file all 649 pokemon new
Often includes Mythical Pokémon that are normally unobtainable without special events. Where to Find "All 649" Save Files Several repositories offer "God Saves" or completed Pokédex