Here is the full list of all 35 A Plague Tale: Requiem achievements. It takes around 20-25 hours to unlock all of the achievements on Windows.
Interact with all the old protector’s items in the sanctuary
Craft 100 ammunitions
Open all the secret chests
Fully improve the Prudence skills
Fully improve the Opportunism skills
Successfully complete all throws in the Crowns game
Find all feathers
Recall all souvenirs
Find all flowers
Complete all chapters
Complete chapter 16
Complete chapter 15
Complete chapter 14
Complete chapter 13
Complete chapter 12
Complete chapter 11
Complete chapter 10
Extinguish 40 fires
Fully improve the Aggressive skills
Complete chapter 9
Complete chapter 8
Complete chapter 7
Complete chapter 6
Fully upgrade the crossbow
Complete chapter 5
Complete chapter 4
Don't kill the guard on the docks
Complete chapter 3
Fully upgrade the instruments
Fully upgrade the gear
Fully upgrade the alchemy
Fully upgrade the sling
Complete chapter 2
Complete chapter 1
Shoot all the pine cones