Windows key is used as Super Key.
Ctrl + Alt + Delete :Restart the computer immediately, without saving open files
Ctrl + Alt + D: Toggles 'Show Desktop'
Ctrl + Alt + L: 'Lock Screen'
Super + S: Zoom out, show workspace switcher
Ctrl + B: Make the selected text bold
F7: Check the spelling of the current document
Mouse-Middle Button: To paste a copied text
Ctrl+HOME: go to start of the command line
Ctrl+END: go to end of the command line
Ctrl+L: Clear Screen
Ctrl + R: Reload the current page