Windows Key + C - Displays the Charms bar. You can navigate through the charms with the arrow keys on your keyboard.
Windows Key + Q = Launches the General Search. You can use this to search for files and settings on your PC, the Internet, and OneDrive, as well as through installed apps and the Windows Store.
Windows Key + F = Launches the Files Search. You can use this to search for files on your PC and OneDrive.
Windows Key + W = Launches the Windows Settings Search. You can use this to search for specific operating system settings by typing in certain keywords.
Windows Key + I = Displays the Settings charm. When using it on the Desktop, you can use this charm to access the Control Panel, Personalization options, the System information section and the Windows Help and Support module. You also have access to the wi-fi settings, volume and brightness control, notifications, power buttons and keyboard settings. When using it from the Start screen, you can use this charm to access the Start screen personalization options, tiles settings and the online help version for the Start screen. You can also use it when working with Windows 8.1 apps to access their settings.
Windows Key + H = Launches the Share charm. When using it on the Desktop, you can use this charm to share a desktop screenshot through the Mail app or other social network app that you have installed. When using it on the Start screen, you can use it to share a screenshot of the Start screen through the same channels. You can also use it to share data from Windows 8.1 apps that you are running.
Windows Key + K = Displays the Devices charm. Depending on the peripherals you have attached to your computer or Windows 8.1 device, you will have the option to play multimedia files, print information from modern apps or show the information on your screen on another display or video projector. This charm can only be used in modern Windows 8.1 apps.
Windows Key + Z = When using it on the Start screen, it displays the Start screen customization button at the bottom of the screen. When using it in modern apps, it displays different contextual options for each app.