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.
Revive a teammate in a multiplayer match.
Fully mod and completely upgrade all weapons.
Find all documents, relics and GPS caches.
Kill 40 enemies with the shotgun.
Kill and loot 10 flying animals (crows and gulls).
Purchase all skills in all categories.
Find 75% of GPS caches.
Complete the game.
Collect 75% of all relics.
Find 75% of all documents.
Fully mod and completely upgrade any weapon.
Complete all optional tombs.
Purchase all skills in one category.
Kill FeeFee the crab.
Kill and loot 10 large animals (deer, boar, wolves).
Kill and loot 10 small animals (rabbits, chickens, rats).
Loot 200 enemies.
Kill 75 enemies with the rifle.
Kill 25 unaware enemies.
Kill 50 enemies with the bow.
Collect 5000 pieces of salvage.
Find 25% of GPS caches.
Collect 25% of all relics.
Perform 15 finishers.
Kill 35 enemies with the pistol.
Perform 50 headshot kills in the single player campaign.
Find 25% of all documents.
Complete one challenge.
Complete one optional tomb.
Force an enemy to drop dynamite that kills two people when exploding.
Rope pull 5 enemies off edges.
Shoot 10 enemies off zip lines.
Incapacitate 25 enemies with dodge counter.
Complete all challenges.
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.
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.