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