The Apache JMeter™ application is open source software, a 100% pure Java application designed to load test functional behavior and measure performance. It was originally designed for testing Web Applications but has since expanded to other test functions.

k6 Open Source is designed for load testing. Extensible to support other types of testing.

Free and open source. Solve accessibility issues before they reach your customers.

For those more detailed screen recordings like demos as well as bugs. Has a built in editor.

Robot Framework is a generic open source automation framework. It can be used for test automation and robotic process automation (RPA).

Orderly Ape is an open source (MIT) tool to run distributed and scalable k6 load tests on your own infrastructure using k6, kubernetes, grafana and influxdb.