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.
Catch a player in a snare trap in multiplayer.
In multiplayer, be the only player on your team that isn't dead or downed.
Fully mod and completely upgrade all weapons.
Find all documents, relics and GPS caches.
Fully mod and completely upgrade any weapon.
Purchase all skills in all categories.
Complete the game.
Kill 40 enemies with the shotgun.
Kill 35 enemies with the pistol.
Perform 15 finishers.
Kill 75 enemies with the rifle.
Complete all optional tombs.
Loot 200 enemies.
Collect 75% of all relics.
Find 75% of all documents.
Find 75% of GPS caches.
Kill FeeFee the crab.
Kill and loot 10 flying animals (crows and gulls).
Purchase all skills in one category.
Collect 5000 pieces of salvage.
Shoot 10 enemies off zip lines.
Force an enemy to drop dynamite that kills two people when exploding.
Find 25% of GPS caches.
Collect 25% of all relics.
Perform 50 headshot kills in the single player campaign.
Kill 25 unaware enemies.
Kill and loot 10 small animals (rabbits, chickens, rats).
Kill 50 enemies with the bow.
Find 25% of all documents.
Complete one optional tomb.
Kill and loot 10 large animals (deer, boar, wolves).
Complete one challenge.
Rope pull 5 enemies off edges.
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.
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.