Toggle Extend Selection Mode

Using the Toggle Extend Selection Mode Shortcut

Windows keyboard shortcut

 
Mac keyboard shortcut

This Excel shortcut removes the need to press Shift to extend the current selection when enabled.
Discover 242 Excel Keyboard Shortcuts for Windows and Mac
Other useful Extending Selection keyboard shortcuts
Extend Selection to the Last Cell Up
Extend Selection to First Cell in Worksheet
Extend Selection Down One Screen
Extend Selection Right One Screen
Extend Selection to the Last Cell Right