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.
Complete all challenges.
Find all documents, relics and GPS caches.
Purchase all skills in all categories.
Complete all optional tombs.
Find 75% of GPS caches.
Collect 75% of all relics.
Fully mod and completely upgrade any weapon.
Kill and loot 10 flying animals (crows and gulls).
Kill and loot 10 large animals (deer, boar, wolves).
Find 75% of all documents.
In multiplayer, be the only player on your team that isn't dead or downed.
Complete the game.
Collect 5000 pieces of salvage.
Complete one challenge.
Find 25% of GPS caches.
Loot 200 enemies.
Kill 40 enemies with the shotgun.
Purchase all skills in one category.
Kill 75 enemies with the rifle.
Kill FeeFee the crab.
Kill 50 enemies with the bow.
Force an enemy to drop dynamite that kills two people when exploding.
Kill 25 unaware enemies.
Collect 25% of all relics.
Perform 15 finishers.
Find 25% of all documents.
Kill and loot 10 small animals (rabbits, chickens, rats).
Perform 50 headshot kills in the single player campaign.
Kill 35 enemies with the pistol.
Complete one optional tomb.
Fully mod and completely upgrade all weapons.
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.