If you need workflows, there's also VisualReview [1] with some basic workflow for approval testing, and Applitools [2], a commercial tool with integration with Selenium, Appium and Protractor that can do screenshot and video comparisons. I wrote about them as part of the 'Automated testing: back to the future' tools review [3]. In the article, I also mentioned DomReactor, but that seems to be discontinued now.
[1] https://github.com/xebia/VisualReview
[2] https://applitools.com/
[3] https://gojko.net/2015/11/16/automated-testing-future/