Here is the full list of all 24 Nadir: A Grimdark Deckbuilder achievements.
Play the Saint's Blood card
Defeat Chernobog
Defeat King in Yellow
Defeat Koschei the Immortal
Defeat Asmodeus
Defeat Lilith
Defeat Minos
Unlock Hernan Cortes as a playable character
Defeat Moloch
Earn any Desires for the first time
Earn any Idols for the first time
Obtain any Rare card
Defeat Abaddon
Unlock Vlad Tepes as a playable character
Defeat Fury
Defeat the Gunnery Demon
Earn any Skulls for the first time
Defeat Beelzebub
Defeat Belzebub
Possess a Damned as a reward
Purchase any card in the shop
Defeat Feaster from Afar
Earn any Relics for the first time
Earn any Filth for the first time