Here is the full list of all 51 Spirited Thief achievements.
Complete a level after collecting all loot and secrets and completing all objectives
Loot a Secret Statue
Scout a level entirely
Complete a perfect run of 5 different levels
Complete a perfect run of all levels
Loot a Mysterious Statue
Loot an Enigmatic Statue
Buy an ability in Sunyang's shop
Buy 5 abilities in Sunyang's shop
Buy everything in Sunyang's shop
Stun an enemy that is threatening you
Kill an enraged enemy
Kill an enemy by "accident"
"Disable" a sorceress' tome
Stun or kill a glued enemy
Kill 5 enemies during one of your turns
Trigger a glyph
Trigger the stun effect of a Chaos Glyph
Go through an alarmed door while invisible
Banish a hostile spirit
Banish a possessing spirit
Loot the Secret Stash and escape
Find hidden information and escape
Find a keepsake and escape
Stun the Sheriff and escape
During Prologue, explore the woods
Complete Prologue without using Stunning Strike
During Onyx, lock the guard carrying the round key in the library
Complete Emerald without keys
During Dream, alert a guard
Complete Topaz without a square key
Complete Amethyst without a round key
Have a team of spirits
Complete Ruby after stealing every single key
Complete Escape! with no guard left alive
Complete Sapphire without keys
During Malachite, steal at least 100 gold on the first turn of loot phase
Complete Pearl without killing an old friend
Complete Mana Stone carrying all rune keys
Complete Soul Lantern with 7 items carried by one character
Complete Mana Bracelets without keys
Complete Ritual at danger level 1
Complete Ravens without letting the spirits kill anyone
During Cave, explore the woods
Complete Shop Attack with all sharpshooters dead
Complete Burrow Spiders after letting a spirit kill the 2 leaders
During Guards' Tower, have the Sheriff let you escape
Complete Thieves Guild without opening the vault's barrier
Complete the game
Complete the game with the "team" ending
Stun an enemy with another enemy