Greenshot - Greenshot is a free and open source screenshot tool that allows annotation and highlighting using the built-in image editor.
Shottr - Shottr is a free macOS screenshot app with scrolling screenshots, OCR, annotation and measurement instruments.
Shutter - Shutter is a feature-rich screenshot program.
AppLaunchpad - Create free beautiful screenshots for App store/Google play
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
TakeaScreen - Take & capture screenshots like a Pro!