I like to label linux hidden files (files and folders starting with a dot) so they appear in lighter gray.
For this just create a new label (ex named 'linuxhidden') and set colors you like.
Create a new wildcard label using regular expression and select linuxhidden
Use this expression if you like only to label files/folders with the dot:
...or use this if you like to label files/folders and all subfiles/subfolders of folders with a dot
Feel free to post other useful wildcard.