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