Qalculate! - Qalculate! is a multiplatform multi-purpose desktop calculator.
React Native - A framework for building native apps with React
GetBricksApp - Bricks is a note-taking web app with a built-in calculator. It can be installed as a desktop or mobile app, because of PWA technology this app built with. Which is also makes it offline available. Notes created with Bricks can be shared.
Deco IDE - Best IDE for building React Native apps
PyCharm Community Edition - "The intelligent Python IDE with unique code assistance and analysis, for productive Python development on all levels."
React Boilerplate - Offline-first, highly scalable foundation for your next app