Quick, clean, and to the point

Repeat last action

Windows shortcut 
Mac shortcut 

This shortcut will repeat the last action again, when available. For example if you just applied a border and red fill to one cell, you can use this shortcut to apply the same formatting to one or more selected cells.

On Windows, you can also use Control + Y for this shortcut. You can add the "Repeat" command to the Quick Access Toolbar to see when an action can be repeated — when it's possible to repeat an action, the command will highlight and become available.

On a Mac, the number of actions that can be repeated is more limited.

Related videos

The videos below show how this shortcut can be used.
In this video, we cover shortcuts you can use to undo, redo, and repeat actions.