Full list of all 23 Destiny 2 achievements worth 1,240 gamerscore. It takes around 80-100 hours to unlock all of the achievements in the base game on Xbox One.
The base game contains 13 achievements worth 1,000 Gamerscore, and there is 1 DLC pack containing 10 achievements worth 240 Gamerscore.
Encounter an Agent of the Nine somewhere in the system.
Acquire each Warlock subclass.
Acquire each Titan subclass.
Complete the "Light Reforged" quest.
Complete 30 challenges.
Complete a Nightfall strike.
Collect 15 Red War exotic weapons or armor.
Complete 5 Heroic Public Events.
Reach level 20.
Acquire each Hunter subclass.
Complete a Heroic public event.
Complete a Nightfall strike on Master difficulty.
Complete a Nightfall strike on Grandmaster difficulty.
Earn 5,000 Triumph points.
Enter the Dreaming City.
Collect 10 Forsaken Exotic weapons or armor.
Complete a Triumph Seal.
Complete a Collections Badge.
Collect 15 Forsaken Exotic weapons or pieces of armor.
Win a Gambit match.
Defeat a Forsaken Nightfall Boss.
Complete the "Shattered Throne" dungeon.
Complete the "Last Wish" Raid.