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