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