Here is the full list of all 35 Winter Ember achievements.
Got the Closure ending
Got the Final Nail ending
Completed the game on Faceless Man difficulty
Got the Divided Nature ending
Got buried alive
Found all 10 feline paintings
Collected all blueprints
Caused Izyus, the High Priest, to fall from a height
Killed or knocked out 5 enemies within 5 seconds
Completed all three mad scientist questlines
Maxed out one of your skill trees
Killed an enemy with a log
Caused an explosive barrel to blow and damage Battista
Killed 20 enemies with a throwing knife
Saved the civilians from being executed during the Evening Purge.
Visited where your family rests
Located Francis Toussaint
Extinguished 50 light sources using water arrows
Knocked out 50 enemies
Set 5 targets on fire
Pickpocketed 100 gold
Disarmed 5 bear traps
Created an arrow with two or more components.
Sold 10,000 worth of items to the Black Market
Successfully lockpicked 3 hard locks
Killed 50 enemies
Hid 5 bodies in tall grass
Knocked out 20 enemies
Used 5 rope arrows to climb
Successfully parried 30 enemies
Killed 30 enemies
Caused an enemy to slip
Performed 5 stealth kills from cover
Performed 20 stealth kills
Performed 10 stealth kills