Show Desktop For Mac?

Windows+D? Huh. Never knew about that - only Windows+M.

Wouldn't what you're looking for be Expose'?

there is no exact shortcut like that but there are a number of alternatives. commandoptionM will minimize all windows of the current app. command+H will hide (without minimizing) all windows of the current app and commandoptionH will hide all the apps besides the current one. there is also exposé which lets you make a number of useful shortcuts like one that shows desktop. lastly there are Spaces.

Hold down the option key then click the mouse cursor anywhere on the Desktop, even if it's just a little piece showing in a corner. All appp will hide and you will go right to the Finder or Desktop if you didn't have a finder window open.

With Expose enabled F11 key will move all windows in every application out of the way to expose the desktop and the files on it.

Expose can be enabled in System Preferences. You can select the key that performs the "show desktop" function from within the Expose preferences.

Hope this helps.