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.

Watir - Watir stands for Web Application Testing In Ruby. It facilitates the writing of automated tests by mimicking the behavior of a user interacting with a website. CommunityWatir stands for Web Application Testing In Ruby.

UFT - United Federation of Teachers: A Union of Professionals

Retest - Retest allows you to check your web apps user experience and deliver absolute masterpieces on multiple devices so that every time your customer visits your webpage, they feel what you want them to feel with your design irrespective of their device

Katalon - Built on the top of Selenium and Appium, Katalon Studio is a free and powerful automated testing tool for web testing, mobile testing, and API testing.

Codeception - Codeception is a new full-stack testing PHP framework.