Applitools Eyes - Automated visual application testing and monitoring
Selenium - Selenium automates browsers. That's it! What you do with that power is entirely up to you. Primarily, it is for automating web applications for testing purposes, but is certainly not limited to just that.
recheck-web - recheck for web apps – change comparison tool with local Golden Masters, Git-like ignore syntax and "Unbreakable Selenium" tests.
DalekJS - DalekJS is an open source UI testing tool.
Imagium.io - Accelerate your software testing process with one of the most advanced visual comparison tool from the future
Webinject - WebInject is a free tool for automated testing of web applications and web services.