GIMP - GIMP is a multiplatform photo manipulation tool.

Surge for Mac - Advanced Web Debugging Proxy for Mac & iOS

Krita - Krita is a professional FREE and open source painting program. It is made by artists that want to seaffordable art tools for everyone. Concept art. texture and matte painters, illustrations and comics.

Weer - A HTTP protocol debugger with Chrome DevTools frontend interface

MyPaint - MyPaint is a fast, distraction-free, and easy painting tool for digital artists.

Cellist - Cellist is an all-in-one HTTP debugging proxy software designed for OS that provides a straightforward approach to put a proxy between the HTTP client and the internet.