This KML network link displays a map overlay for Maps-For-Free Relief (https://www.maps-for-free.com/) in Google Earth.
For some information on how it works, please see the 
To get started, simply download 
maps-for-free-relief-overlay-for-google-earth.kmz (please log in first, see here why) and open it in Google Earth. Or checkout
Do you have comments, bug reports, or suggestions for other map sources? Please leave them below.