Custom Shape Tool
Did you know that in addition to photo editing, you can also easily add shapes and design elements to your Photoshop creations by using Custom Shape Tool? The Tool Panel has all of the basic shapes you need like square, line, circle, ellipse etc in addition to a whole slew of extended options. The Custom Shape tool is easy to find in the Options Bar, represented by an icon that kind of looks like a puzzle piece.
Access even more shapes by clicking again on the small arrow on the right side of the panel. If you are looking for banners, speech bubbles or arrows of all kinds, this is just the tool for you.