Is there a way to tag folders with colors?
Is there any app that could set label color for individual file/folder like in Mac OS X?
No, but you can add emplems, which are small icons to be added on top of the file icon. You've seen that in your home directory. The music directory has an extra symbol, the documents folder, etc.
You can find out how to add such emblems here: Is there any tweak to bring back emblems in Nautilus?