Snorlax

Once the King of GSC OU, Snorlax took quite a few hits with each subsequent generation, finally dropping to UU along with long-time fellow OU Pokemon, Zapdos, in BW. With the rising popularity of Fighting-types, it struggles to maintain a big presence on the battlefield. Furthermore, lack of reliable recovery really hurts its durability—especially with the BW sleep mechanics. However, its amazing HP stat and great special bulk make it one of the few able to reliably check a complete offensive spectrum, taking on special powerhouses such as Nidoking or Zapdos. Snorlax is also one of the most trustworthy answers to Victini, one of the biggest threats in the metagame. With its good base 110 Attack stat, it can keep offensive pressure with ease, be it with a Choice Band or by setting up with its old Curse set.

Taking everything previously stated into account, Snorlax continues to be a great addition to any team, countering specific prominent threats, such as Offensive Trick Room Cofagrigus or Substitute+Calm Mind Raikou, very aptly. Even though it's much less metagame-defining than it once was, it can take credit for being a staple of the Underused metagame and one of the most used Pokemon overall.