Here is the full list of all 23 Emberglass achievements.
You have found the haunted lantern
You have found the bow hewn from living oak
You have found the bones of the Hollow Princess, whose ghost will shield you from harm
You have discovered the lost sword of the Hollow Prince
You have found the wings of crow flight, given from Queen Maab to her sisters.
You have discovered the ring that summons the rain
You have discovered the ring the summons the fog.
You have discovered the wand that grows vines
You have found all the potions
You have discovered all the quivers in the game
You have discovered the Tomb of the Hollow Prince
You have discovered the Secret Graveyard
You have collected over 25 bones and skulls
You have beaten the game without killing a single enemey
You have killed over 25 bats
Beat the game only using bones, skulls, and the ghost shield items
You have unlocked the mist key door
You have killed over 25 ghosts
The first guardian of shadows is dead
The second guardian of shadows is dead
The third guardian of shadows is dead
You have achieved the good ending
You have achieved the band ending