Here is the full list of all 50 Tomb Raider achievements. It takes around 40-50 hours to unlock all of the achievements on Windows.
In multiplayer, be the only player on your team that isn't dead or downed.
Find all documents, relics and GPS caches.
Complete the game.
Complete all challenges.
Complete all optional tombs.
Fully mod and completely upgrade all weapons.
Purchase all skills in all categories.
Kill 75 enemies with the rifle.
Fully mod and completely upgrade any weapon.
Collect 75% of all relics.
Find 75% of all documents.
Kill 40 enemies with the shotgun.
Find 75% of GPS caches.
Kill FeeFee the crab.
Loot 200 enemies.
Purchase all skills in one category.
Force an enemy to drop dynamite that kills two people when exploding.
Collect 5000 pieces of salvage.
Kill 35 enemies with the pistol.
Perform 50 headshot kills in the single player campaign.
Kill and loot 10 flying animals (crows and gulls).
Find 25% of GPS caches.
Collect 25% of all relics.
Complete one challenge.
Kill and loot 10 small animals (rabbits, chickens, rats).
Kill and loot 10 large animals (deer, boar, wolves).
Perform 15 finishers.
Kill 25 unaware enemies.
Kill 50 enemies with the bow.
Complete one optional tomb.
Find 25% of all documents.
Rope pull 5 enemies off edges.
Shoot 10 enemies off zip lines.
Incapacitate 25 enemies with dodge counter.
Shoot a bundle of dynamite out of the air.
Complete all conversations with the Endurance crew.
Complete a match in all multiplayer modes.
Kill 20 enemy players in multiplayer using a turret.
Kill a zip-lining enemy player in multiplayer.
Catch a player in a snare trap in multiplayer.
Survive 10 explosions in multiplayer.
Revive a teammate in a multiplayer match.
Win a ranked match in every multiplayer mode.
Kill 10 multiplayer enemies using your melee attack.
Kill 2 multiplayer enemies with a single explosive.
In multiplayer, escape death 3 times by using the rope ascender.
Purchase a new multiplayer character.
Reach level 10 in multiplayer.
Buy every upgrade and character in multiplayer.
Reach level 60 in multiplayer.