Here is the full list of all 38 Thief trophies - there are 24 bronze, 8 silver, 5 gold and 1 platinum.
The True Master Thief
Score an epic 5,000,000 or more in a Challenge Map
Use 40,000 gold
Complete all collectible sets
Discover all secret areas
Complete all Client Jobs in The City
Complete a collectible set
Complete all Basso Jobs in The City
Pick 100 pockets in a single playthrough
Complete 25 optional Thieving Challenges
Find all the secret stashes in Moira
Complete 10 optional Thieving Challenges
Steal all loot and collectibles in a single chapter
Pick a pocket and a lock using the focus ability
Shoot a bottle in mid-air with an arrow
Finish the game with a custom difficulty of 700 points or more
Finish the game without a single kill or knockout
Finish the game on Master difficulty
Reach the final chapter without using the focus ability
Finish 3 consecutive missions without taking damage
Finish a single chapter without alerting anyone
Uncover Lyegrove's secret
Finish Chapter Eight
Finish the game in 15 hours or more
Finish Chapter Seven
Finish Chapter Six
Discover 15 secret areas
Disarm ten trap mechanisms
Finish Chapter Five
Finish Chapter Four
Finish Chapter Three
Pick a lock with masterful speed
Kill or knockout 10 people using the environment
Finish Chapter Two
Steal 5 collectibles
Sweet sixteen. Snuff said.
Finish Chapter One
Finish the Prologue