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