If use you the color labels on your files on the Mac, it turns out that you can search for files by color label in Spotlight. Just enter the search term: label:x where x is a number from 0 - 7 corresponding to the color label you want to search on. The correspondence between numbers and colors is like so:

0 = No color label1
1 = Gray
2 = Green
3 = Purple
4 = Blue
5 = Yellow
6 = Red
7 = Orange

You can combine label search with other Spotlight searches in the usual manner so that you can always limit your search results by label.