Lightshot is the fastest way to take a customizable screenshot. Simple interface, nothing useless and light weight.

Gyazo is an open source screenshot program for Windows, Mac OS X and Linux.

Awesome Screenshot is the highest-rated screen capture & image annotation tool on Chrome with over 2 million users.

Grabilla is a software that takes a screenshot of the user's computer screen and uploads it to the Web, FTP, computer or copy to clipboard.