Full list of all 23 Destiny 2 achievements. It takes around 200 hours to unlock all of the achievements in the base game on Windows.
The base game contains 13 achievements, and there is 1 DLC pack containing 10 achievements.
Complete the Leviathan raid.
Complete the Leviathan raid on Prestige difficulty.
Acquire each Titan subclass.
Acquire each Warlock subclass.
Reach level 20.
Acquire each Hunter subclass.
Complete Introduction: Crucible.
Complete a Flashpoint on Earth, Titan, Nessus, or Io.
Complete a Heroic public event.
Complete a Nightfall strike.
Collect 15 Red War exotic weapons or armor.
Complete 30 challenges.
Encounter an Agent of the Nine somewhere in the system.
Complete the "Last Wish" Raid.
Complete a Triumph Seal.
Collect 10 Forsaken Exotic weapons or armor.
Defeat a Forsaken Nightfall Boss.
Complete a Collections Badge.
Earn 5,000 Triumph points.
Enter the Dreaming City.
Complete a Forsaken Exotic Quest.
Win a Gambit match.
Pursue Uldren and the Fanatic to the Watchtower, and finish what you started.