Burp or Burp Suite is a set of tools used for penetration testing of web applications. It is developed by a company named Portswigger who make freely available a Web Security Academy which has a range of lessons on penetration testing.

Maestro is a mobile UI testing framework. It's built on learnings from its predecessors (Appium, Espresso, UIAutomator, XCTest) and allows you to easily define and test parts of your user flow.

API Testing Platform that automatically generates unit test cases with dependency mocks from API calls

Bruno is a Fast and Git-Friendly Opensource API client, aimed at revolutionizing the status quo represented by Postman, Insomnia and similar tools out there.

Streamline your API testing, integration testing and test data management.

Hand-crafted lightweight Rest Client for testing APIs. Supports collections, environments, git collaboration and local storage.