Tiny Flashlight + LED - Tiny Flashlight + LED is free to use application that can be used anywhere else, having nicely built-in functionality.

Greenshot - Greenshot is a free and open source screenshot tool that allows annotation and highlighting using the built-in image editor.

Hmu - Hmu is a social app by SC Friends that enables users to search for new friends by viewing a list of users from all around the globe and tap on the desired profile to engage in live chat with them.

Shutter - Shutter is a feature-rich screenshot program.

Flashlight - Control your Mac with a keystroke.

Snipping Tool - Use Snipping Tool to capture a screen shot, or snip, of any object on your screen, and then annotate, save, or share the image