Here's a great resource I ran across... https://toolbox.google.com/datasetsearch
It helped me find the web server with very many layers (many of them very specialized, but still interesting) that is in the attached mxb.
That particular project uses the lat/lon projection version. Connecting to the WMTS server using pseudo mercator as usually done results in strange scaling. That's being worked on to find out what the issue is.
But... for now, the lat/lon layer re-project just fine on the fly.
Attachments: Global Imagery Browse GIBS 4326.mxb