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