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 Taken King" quest.
Complete "The Stormcaller's Path" quest.
Complete "The Sunbreakers' Challenge" quest.
Complete "The Nightstalker's Trail" quest.
Complete "The Old Hunger" quest.
Complete the "Echoes of Oryx" quest.
Complete the King's Fall Raid.
Complete the King's Fall Raid (Heroic).