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