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.
Win a ranked match in every multiplayer mode.
Revive a teammate in a multiplayer match.
Kill 2 multiplayer enemies with a single explosive.
In multiplayer, be the only player on your team that isn't dead or downed.
Complete a match in all multiplayer modes.
Survive 10 explosions in multiplayer.
In multiplayer, escape death 3 times by using the rope ascender.
Complete all challenges.
Fully mod and completely upgrade all weapons.
Find all documents, relics and GPS caches.
Complete the game.
Fully mod and completely upgrade any weapon.
Purchase all skills in all categories.
Kill 40 enemies with the shotgun.
Find 75% of all documents.
Complete all optional tombs.
Find 75% of GPS caches.
Collect 75% of all relics.
Force an enemy to drop dynamite that kills two people when exploding.
Kill and loot 10 flying animals (crows and gulls).
Complete all conversations with the Endurance crew.
Kill FeeFee the crab.
Kill 75 enemies with the rifle.
Loot 200 enemies.
Kill 25 unaware enemies.
Purchase all skills in one category.
Collect 5000 pieces of salvage.
Incapacitate 25 enemies with dodge counter.
Shoot 10 enemies off zip lines.
Rope pull 5 enemies off edges.
Shoot a bundle of dynamite out of the air.
Find 25% of GPS caches.
Kill 50 enemies with the bow.
Kill 35 enemies with the pistol.
Kill 20 enemy players in multiplayer using a turret.
Kill a zip-lining enemy player in multiplayer.
Kill 10 multiplayer enemies using your melee attack.
Reach level 10 in multiplayer.
Purchase a new multiplayer character.
Catch a player in a snare trap in multiplayer.
Kill and loot 10 small animals (rabbits, chickens, rats).
Collect 25% of all relics.
Perform 15 finishers.
Perform 50 headshot kills in the single player campaign.
Find 25% of all documents.
Complete one challenge.
Kill and loot 10 large animals (deer, boar, wolves).
Complete one optional tomb.