Greenshot - Greenshot is a free and open source screenshot tool that allows annotation and highlighting using the built-in image editor.
ShareX - ShareX is a free and open source program that lets you capture or record any area of your screen...
Capture2text - Capture2Text enables users to quickly OCR a portion of the screen using a keyboard shortcut.
ksnip - Ksnip is a Qt based cross-platform screenshot tool that provides many annotation features for your screenshots. - DamirPorobic/ksnip
LightShot - The fastest way to take a customizable screenshot.
Easy Screen OCR - Easy Screen OCR helps users capture screenshot and grab text from images.