Beyond the main studio releases, there are several exclusive compilations that every completionist needs:

"Merry Christmas, Happy Holidays," "Under My Tree." The Vibe: Cozy, soulful, and vocal-centric. 3. The Winter Album (1998 - International Exclusive)

* The Essential NSYNC (2014): A comprehensive 2-CD set that includes rare b-sides like "Better Than E-Z" and soundtrack contributions like "Music of My Heart." Why NSYNC Still Matters