Crafted: orange -> cyan
Normal 
Unique 
Rare: blue -> pink/magenta
Legendary 
Set:
otherwise green -> lime (doesn't matter)
Fabled 
Mythic: pink -> purple
I don't know how this even came to be in the first place. Of course, it goes without saying, that there may be other inaccuracies and issues with the Trade Market's item filter (ender pearls...) that I haven't touched on