There's the
Achievements (some are outdated).
There's the non-achievements in the game:
1: Complete every quest
2: Find every secret
3: Kill every unique boss
4: Complete every Town Hall Quest (caution some have negative reputation)
5: Complete the game as every Class
6: Complete the game without every getting a Companion
7: Complete the game under 100 in-game days, under 50 in-game days.
8: Beat the game without any Advanced Skills.
9: Find the Invisible Swamp Donkey
10: Buy both houses in the game
11: Buy / find / loot every top tier / unique item (Ankh of Life, Force Belt, Ivory Ring, Greater Ring of Endurance, Adamintite Sword, Ark weapons, Ring of Unlife, etc)