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