ShareX - ShareX is a free and open source program that lets you capture or record any area of your screen...
browserling - Live interactive cross-browser testing from your browser.
Thum.io - A real-time website screenshot generator
BrowserStack - BrowserStack is a software testing platform for developers to comprehensively test websites and mobile applications for quality.
Picmaker - Design the Future
Browsershots - Browsershots makes screenshots of your web design in different browsers.