Quick-select hidden tools in Photoshop to speed up your editing workflow
Many of the tabs in the Toolbar hide more than one tool, such as the Marquee selection options.
To access these while working on an image, hold the Shift key and press the shortcut key multiple times to cycle through the other tools within that tab.
There is an alternative to this. If you go to Edit>Preferences>General and uncheck the box that says Use Shift Key For Tool Switch, you can cycle through to the next tool by just pressing the keyboard shortcut letter again.