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.
StresStimulus - Load testing tool for websites and mobile that works with hard-to-test applications.
TestComplete - TestComplete Desktop, Web, and Mobile helps you create repeatable and accurate automated tests across multiple devices, platforms, and environments easily and quickly.
OctoPerf - OctoPerf is a SaaS load testing solution, based on JMeter.
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.
SmartMeter.io - Performance Testing with Enterprise-Level Features with a familiar jMeter interface