To obtain a Pokémon White 2 save file with all 649 Pokémon (the full National Pokédex for Generation 5), you can either download a pre-made save file or use a save editor to modify your own. Pre-made Save Files
Competitive Breeding: Most "All 649" save files include a 6-IV Japanese Ditto, making it easy to breed competitive-ready Pokémon using the Masuda Method.
Maximum Resources: These files typically include 999 of all items, including Master Balls, TMs, and rare berries. How to Use
Several platforms host completed save files that include all 649 Pokémon, often with 8 badges and post-game content unlocked.
A "100% complete" save file typically offers more than just a full Pokédex. These files often include: