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.
Apache JMeter - Apache JMeter™.
Cucumber - Cucumber is a BDD tool for specification of application features and user scenarios in plain text.
Ranorex - Ranorex is a GUI test automation framework for testing of desktop, web-based and mobile applications.
locust - An open source load testing tool written in Python.
Endtest - Intelligent Test Automation