Here are some Windows 8 keyboard shortcuts I found out via the process of trial and error. Some are more useful than others and some are indispensable.
Windows 8 Shortcuts – Using Windows Key
Very Useful
Windows Key + S Start Menu
Windows Key + D Desktop
Windows Key + C Charms Accesses Settings for current App
Windows Key + Tab Apps Slider at left side, to change Apps
Quite Useful
Windows Key + F Files menu, at right side
Windows Key + X Useful list of options from Desktop to Programs & Features
Windows Key + M Minimize current App
Windows Key + P Project to another screen
Windows Key + I Settings
Windows Key + U Accessibility
Windows Key + R Run – run programs etc
Windows Key + E Computer window appears
Windows Key + W Settings
Windows Key + Q All Apps list appears
Nice to Know
Windows Key + L Lock Screen