Here is the full list of all 88 Idle Banshee Alliance achievements.
Tortoise beast
Hare demon
Pig demon
snaker
Sprite
Ratbat
werewolf
Canine demon
HawkGirl
Cat demon
Sheep Girl
Cattle demon
Deer demon
Sea demon
Yuki-onna
Bear Girl
Monkey demon
faker
spider goblin
Demon fox
vampire
Horse demon
dragon lady
Butterfly essence
Lion demon
A dull duck
Elephant Girl
Black crow
Fire Phoenix
Demon
Crane demon
unicorn
Shark demon
Crocodile demon
Whale demon
Lizard Beast
Ridgeback
Ironclad beast
Ostrich demon
Scorpion essence
Tyrannosaurus Rex
Stegosaurus
Triceratops
brontosaurus
Carcharodontosaurus
Mammoth
Sabre Wulf
Phobic elephant
Bighorn deer
Ancient monitor lizard
Typhon
Empusa
Skura
Medusa
chimera
Divine Beast - Dragon
Divine Beast - White Tiger
Divine Beast - Rosefinch
Divine Beast - Xuanwu
Divine Beast - Kylin
Chelsea
Satan
Sariel
Samle
Abraham
Bael
Pthahnil
Azathoth
Yog-Sothoth
Shub-Niggurath
Nyarlathotep
Nyog'Sothep
Abhoth
Ghroth
Tulzscha
Yidhra
Daoloth
A banshee has 16 skills
10 Star Killer
All banshees reached full level
All banshees have 16 skills
Endless reach 100 layers
Breaking the upper limit
Unlock all album pictures
20 Star Killer
30 Star Killer
Alliance
Single-person victory over 30-star god killing mission