John's Background Switcher - Switch backgrounds to trending imgur, reddit, tumblr threads
Jupyter - Project Jupyter exists to develop open-source software, open-standards, and services for interactive computing across dozens of programming languages. Ready to get started? Try it in your browser Install the Notebook.
Unsplash Wallpaper - Gorgeous wallpapers on your Mac
Kajero - Interactive JavaScript notebooks - create good-looking, responsive, interactive documents.
Wallcat - Enjoy a new, beautiful wallpaper, every day.
BeakerX - Open Source Polyglot Data Science Tool