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.
Screenster - 10x faster UI testing without a line of code.
Cypress.io - Slow, difficult and unreliable testing for anything that runs in a browser. Install Cypress in seconds and take the pain out of front-end testing.
Robot framework - Robot Framework is a generic test automation framework for acceptance testing and acceptance...
SlimerJS - A scriptable web browser for web testing, web scraping, network monitoring...
TestComplete - TestComplete Desktop, Web, and Mobile helps you create repeatable and accurate automated tests across multiple devices, platforms, and environments easily and quickly.