Is there a keyboard shortcut to fully hide all windows, showing only desktop?

Solution 1:

⌘+H Hides the windows of the currently running application.

⌥+⌘+H Hides the windows of all other running applications.

Solution 2:

This not simply a keyboard shortcut but it does (I believe) give you the desired result.

1. As many know, holding down the Option key while clicking anywhere outside the current active window will hide the active window. I've been using this for many years.

2. Hold down Command and Option and click on the desktop and all active windows will hide.

I suppose the limitation is that if you can't see a little piece of the desktop somewhere you're sunk (maybe).