Best "simple" screen capturing app (Mac and Windows) because it creates animated gifs that attach to bugs easily. Simple because it works a lot like snippy to capture screen areas

Free & OpenSource REST API Testing Tool for all levels in a Test Pyramid

SeleniumBase Case Plans is Test Case Management Software that uses Markdown tables for displaying test plans directly in GitHub (and other source code management systems that support Markdown format).

View and interact your android device remotely/on your desktop

A screenshot/screenvideo tool! Also allows you to do basic alterations to the screenshots (arrows, blur, ...)

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