Sauce Labs - Test mobile or web apps instantly across 700+ browser/OS/device platform combinations - without infrastructure setup.
CrossBrowserTesting - Browser Testing made simple! Run automated, visual, and manual tests on 1500+ real browsers and mobile devices. Test more browsers, in less time.
LambdaTest - Perform Web Testing on 2000+ Browsers & OS
browserling - Live interactive cross-browser testing from your browser.
Browserless - Headless browser automation built for developers.
Browsershots - Browsershots makes screenshots of your web design in different browsers.