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