Here is the full list of all 12 The Living Remain achievements.
Complete Campaign
Find All Special Items
Stab and Kill an Infected Rat
Collect 50 Filaments
Collect 25 Filaments
Upgrade Any Weapon For The First Time
Fully Upgrade Any Weapon
Use Medkit For The First Time
Find First Special Item
Complete The Tutorial
Watch Ending Credits
Stab and Kill Five Infected Rats