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.

Charles Proxy - HTTP proxy / HTTP monitor / Reverse Proxy

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

HTTP Headers - HTTP Headers allows you to quickly see the HTTP header information for the current URL.