[Diablo 1, Diablo 2]
- Light grey - Trash
- White - Normal (most likely trash)
- Blue - Magic
- Yellow - Rare
- Green - Set
- Golden - Unique
Diablo 3 (basically the same as D1 and D2)
- Light grey - Trash
- White - Normal
- Blue - Magic
- Yellow - Rare
- Green - Set
- Orange - Uniques, now called Legendary
Diablo 4
- Light grey - trash
- White - Normal (trash)
- Blue - Magic (also trash)
- Yellow - Rares (also trash)
- Yellow - Sacred Rares (also trash)
- Yellow - Ancestral Rares
- Orange - Rares with ability, called Legendaries
- Orange - Sacred Legendaries
- Orange - Ancestral Legendaries
- Tan (similar to orange) - Legendaries, now again called Uniques
I guess this is how we roll now. Personally i dislike that uniques and legendaries almost look the same for me colourwise.
Feel free to correct any mistakes i made.