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.
Encounter an Agent of the Nine somewhere in the system.
Complete a Nightfall strike.
Reach level 20.
Acquire each Titan subclass.
Acquire each Hunter subclass.
Acquire each Warlock subclass.
Complete a Flashpoint on Earth, Titan, Nessus, or Io.
Complete a Heroic public event.
Collect 15 Red War exotic weapons or armor.
Complete 30 challenges.
Complete Introduction: Crucible.
Complete the Leviathan raid.
Complete the Leviathan raid on Prestige difficulty.
Pursue Uldren and the Fanatic to the Watchtower, and finish what you started.
Enter the Dreaming City.
Earn 5,000 Triumph points.
Collect 10 Forsaken Exotic weapons or armor.
Complete a Triumph Seal.
Complete a Collections Badge.
Complete a Forsaken Exotic Quest.
Win a Gambit match.
Defeat a Forsaken Nightfall Boss.
Complete the "Last Wish" Raid.