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