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.
Complete a Nightfall strike on Grandmaster difficulty.
Acquire each Warlock subclass.
Complete a Nightfall strike on Master difficulty.
Acquire each Titan subclass.
Collect 15 Red War exotic weapons or armor.
Complete the "Light Reforged" quest.
Complete 30 challenges.
Encounter an Agent of the Nine somewhere in the system.
Complete a Nightfall strike.
Complete 5 Heroic Public Events.
Reach level 20.
Acquire each Hunter subclass.
Complete a Heroic public event.
Complete a Triumph Seal.
Defeat a Forsaken Nightfall Boss.
Collect 10 Forsaken Exotic weapons or armor.
Complete a Collections Badge.
Complete the "Last Wish" Raid.
Collect 15 Forsaken Exotic weapons or pieces of armor.
Win a Gambit match.
Enter the Dreaming City.
Complete the "Shattered Throne" dungeon.
Earn 5,000 Triumph points.