Greenshot - Greenshot is a free and open source screenshot tool that allows annotation and highlighting using the built-in image editor.
MWSnap - MWSnap is basically a free to use Windows snapping tools that are used for snapping any part of the screen that is currently displaying on the front of all opened programs and windows.
FastStone Capture - A powerful, lightweight, yet full-featured screen capture tool that allows you to easily capture...
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
Shutter - Shutter is a feature-rich screenshot program.
LightShot - The fastest way to take a customizable screenshot.