1. Selenium: Selenium is an open-source, automated testing tool that tests web applications across various browsers and platforms. This software is one of the most commonly used software testing tools due to its ability to test functionality, performance, usability, and compatibility with different operating systems.

2. JUnit: JUnit is a Testing Framework developed for Java programming. It is used to write and run repeatable automated tests and measure code coverage.

3. TestComplete: TestComplete is a popular software testing tool that provides cross-platform support, allowing users to automate tests on multiple platforms simultaneously. It also offers advanced editing capabilities, including WhatsApp, keyword testing, and data-driven testing.

4. Apache JMeter: Apache JMeter is a popular open-source load-testing tool for testing web applications and server performance. It enables users to simulate heavy user traffic and measure response times under different conditions.

5. LoadRunner: LoadRunner is a testing tool from HP that simulates a system’s virtual user load. It helps teams identify and fix performance problems before they become an issue for users.