You can assign a function key to run an action when creating an action, or assign one after the fact by double clicking to the right of the action’s name or using the Actions panel’s fly-out and selecting Action Options.
Choose a function key from the list (the number of F-keys will vary depending on platform and keyboard layout) or add a keyboard modifier such as Shift. If you assign a F-key that is already in use by Photoshop (F5 for example, is assigned by default to show and hide the Brush panel), Photoshop will reassign it to your action. Note: different operating systems assign F-keys for certain tasks. To use those F-keys in Photoshop, they must be changed or removed in the operating system).
In addition, use the Action Options to color code actions, making them easily identifiable when viewed in Button Mode.