Tepig: You'll have to trade. Skitty: If you're playing Black 2 (and I assume you are, since you're not asking about Buneary), you'll have to trade. If you're playing White 2, go to the part of Castelia City where wild Eevee can be found. Pinsir: There's a Backpacker in Route 14 that has a Pinsir. You could also climb the waterfall in Lostlorn Forest and battle the trainer there. Shuppet: You'll have to catch a Banette and breed it. Gliscor: You'll have to look in shaking grass in Route 11, Route 15, or Route 23. Seel: You'll have to surf in the Giant Chasm or the Seaside Cave. Dewgong: You'll have to surf in the Giant Chasm or the Seaside Cave, and look in the rippling water. Corphish: There's a Fisherman in the Moor of Icirrus that has a Corphish. Tropius: There's a male Ace Trainer in either Big Stadium or Small Court that has a Tropius. However, you might want to look for a wild Tropius in Route 18 instead.
http://i458.photobucket.com/albums/qq303/CharizardFire6/Char-Brawl.gif The official Charizard of the Pokemon Black 2 and White 2 boards.