- Google ChromeDriver
- Mozilla Firefox Geckodriver
- Microsoft Edge WebDriver (Windows)
- Safari Webdriver (OSX, build in, no need for seperate download)
If you run the test on one machine and i.c.w. Ruby/Watir, you can also use the webdrivers gem. Make sure the webdriver is in a folder that is in the PATH variable.
Selenium-grid: Keep in mind that the webdrivers gem is not going to work here.
Appium: Same for Appium.
Check My blogpost about webdrivers if you want more information about running these with a custom webdirver.