Download Rainbow Folders 2 FREE Unity. 

Have you ever thought about highlighting often used project folders? This simple but colorful asset allows you to do that!

With Rainbow Folders, you can set a custom icon and background for any folder in the Unity project browser.

Just hold the Alt key and click on any of your folders. A configuration dialog will appear, and you’ll be able to assign a custom icon and background for it, your own one or chose from dozens of presets!