Keynote
Use a keyboard shortcut to apply a style in Keynote on Mac
You can assign a shortcut key (F1—F8 on your keyboard) to a paragraph, character, or list style, then use the shortcut key to apply the style to selected text.
Note: To use shortcut keys on a Mac, press Fn with the shortcut key.
To remove a shortcut key assignment, follow the steps above, then choose None from the Shortcut menu.