Photoshop: Cycling through hidden tools

Some of the lesser used tools in Photoshop are grouped under the same button. If you use the mouse, this would normally involve clicking and holding on the button until a list of additional tools pop up.

However for those who use keyboard shortcuts to access these tools, it can be quite confusing as to how to access those hidden tools with the keyboard. To do so, hold down Shift+ to cycle through the tools. For instance, pressing Shift+I for the first time would select the Eyedropper tool, the Color Sampler Tool the second time, and the Ruler Tool for the third time, etc.