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