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

Shutter - Shutter is a feature-rich screenshot program.

ShareX - ShareX is a free and open source program that lets you capture or record any area of your screen...

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

PicPick - PicPick screen capture software enable you to grab an image on your computer screen, save, print, add effects, and share.

LightShot - The fastest way to take a customizable screenshot.