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