While the original Pokemon Black and White contained over 150 new Pokemon and, until after you've beaten the game, allowed you only those Pokemon to catch, Black 2 and White 2 mix many, many different Pokemon into the mix, mixing both newer Unova Pokemon with older Pokemon from various generations. There are at least 300 Pokemon in total in Pokemon Black 2 and White 2's Pokedex!
The starter Pokemon are the same as they were in the original Black and White: Snivy, Tepig, and Oshawott.
Revamped Unova Pokedex
As stated above, there are said to be over 300 Pokemon in the revised Pokedex in the Unova region. You can see that demonstrated on the side, which shows the Pokedex entry for Metagross and listing its number as #264. There are several other confirmed numbers, such as Mareep at #025, Psyduck at #028, Azurill at #030, Riolu at #033, and Arcanine at #052. Many other Pokemon from various regions have been revealed, too.
Could this possibly be a battle against a wild Eevee? Either way, the new battle appearance looks both similar and refreshing at the same time.
While there is likely a much larger list than what's shown, what has been revealed indicates that the following Pokemon are version exclusives to the following versions:
|Black 2-only||White 2-only|
|Black Kyurem||White Kyurem|
|Magby + evolutions||Elekid + evolutions|
|Buneary + Lopunny||Skitty + Delcatty|
|More exclusives are available! I'll list them all shortly after the video coverage is complete.|