The The Taken King Add-on for Destiny has 10 achievements worth 250 gamerscore.
Complete "The Nightstalker's Trail" quest.
Complete "The Taken King" quest.
Complete "The Court of Oryx" quest.
Complete "The Old Hunger" quest.
Complete "The Stormcaller's Path" quest.
Complete "The Sunbreakers' Challenge" quest.
Complete the King's Fall Raid.
Complete the King's Fall Raid (Heroic).
Complete the "Echoes of Oryx" quest.
Complete "The Wolves of Mars" quest.