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