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