Selenium was one of the most popular and widely used frameworks for web browser automation and Testing. It allows you to automate web applications for testing purposes, as well as perform repetitive tasks in a web browser. However, there are also several other testing tools and libraries built on top of Selenium that offer additional features and functionality. Here are some of them:

1. Selenium WebDriver: This is the core Selenium library that provides a programming interface to interact with web browsers. It allows you to write test scripts in various programming languages like Java, Python, C#, etc.

2. Selenium Grid: It is used for running multiple tests across different browsers, operating systems, and machines in parallel, improving test efficiency.

3. TestNG: A Testing Framework inspired by JUnit and NUnit, TestNG can be easily integrated with Selenium for organizing test cases, grouping them, and generating test reports.

4. JUnit: A popular testing framework for Java applications, JUnit can be combined with Selenium to create test suites and run tests.

5. NUnit: Similar to JUnit, but designed for .NET applications, NUnit integrates well with Selenium for testing .NET web applications.

6. Pytest: A popular testing framework for Python, Pytest provides simple and easy-to-use syntax for writing test cases in combination with Selenium.

7. Cucumber: It is a tool that supports Behavior Driven Development (BDD) and allows you to express test scenarios in a natural language format. It can be used with Selenium to write tests in a more human-readable style.

8. Robot Framework: An open-source test automation framework that utilizes a keyword-driven approach, making it easy to create test cases and execute them with Selenium.

9. Protractor: A testing framework specifically designed for Angular applications, Protractor is built on top of WebDriverJS (Selenium WebDriver for JavaScript).

10. WebdriverIO: A Node.js-based testing framework that provides easy-to-use APIs and commands to write Selenium tests with JavaScript.

11. TestCafe: Unlike Selenium, TestCafe does not require browser plugins or driver installations. It supports JavaScript and TypeScript and provides cross-browser testing capabilities.

Please note that the landscape of testing tools is constantly evolving, and new tools may have emerged since my last update. Therefore, it’s always a good idea to check the latest trends and tools in the testing community to find the most suitable one for your specific needs.