The Forsaken Add-on for Destiny 2 has 10 achievements worth 240 gamerscore.
Earn 5,000 Triumph points.
Collect 10 Forsaken Exotic weapons or armor.
Complete a Triumph Seal.
Complete a Collections Badge.
Enter the Dreaming City.
Complete a Forsaken Exotic quest.
Win a Gambit match.
Defeat a Forsaken Nightfall Boss.
Pursue Uldren and the Fanatic to the Watchtower, and finish what you started.
Complete the "Last Wish" Raid.