Alt + Tab

Switches between windows. When you use these shortcut keys, a list of windows that you can select is displayed. Release the keys to select a window. 

Alt + Esc

Switches between windows. Release the keys to select a window. 

F10

Opens the first menu on the left side of the menubar.  

Alt + spacebar

Opens the Window Menu.

Arrow keys 

Moves the focus between items in a menu. 

Return

Chooses a menu item.  

Esc

Closes an open menu. 

Ctrl + Alt + right arrow

Switches to the workspace to the right of the current workspace. 

Ctrl + Alt + left arrow

Switches to the workspace to the left of the current workspace. 

Ctrl + Alt + up arrow

Switches to the workspace above the current workspace. 

Ctrl + Alt + down arrow

Switches to the workspace below the current workspace. 

Ctrl + Alt + d

Minimizes all windows, and gives focus to the desktop.