Here is the full list of all 31 I Am Overburdened achievements.
Unlock the Buzzard Wizard in the Book of Monsters
Unlock all entries in the Book of Monsters
Have 500 gold on you
Select all artifacts randomly in a treasury mode playthrough
Beat the game on nightmare difficulty
Unlock 100 items in the Tome of Artifacts
Unlock 75 items in the Tome of Artifacts
Unlock 50 items in the Tome of Artifacts
Have 350 gold on you
Beat the Crystalline Cavern on nightmare difficulty
Beat the Rusting Fort on nightmare difficulty
Beat the Ancient Tomb on nightmare difficulty
Beat the Ruined Mausoleum on nightmare difficulty
Beat the Decayed Catacombs on nightmare difficulty
Beat the Forgotten Cellar on nightmare difficulty
Unlock 25 items in the Tome of Artifacts
Beat the Dusty Vault on nightmare difficulty
Beat the Howling Barracks on nightmare difficulty
Beat the Filthy Sewers on nightmare difficulty
Beat the Flooded Cave on nightmare difficulty
Beat the game
Beat the Crystalline Cavern
Beat the Rusting Fort
Beat the Ancient Tomb
Beat the Ruined Mausoleum
Beat the Decayed Catacombs
Beat the Forgotten Cellar
Beat the Dusty Vault
Beat the Howling Barracks
Beat the Filthy Sewers
Beat the Flooded Cave