Mac OS X Softwares to Create Custom brushes

SketchPort is a versatile web-based digital drawing application designed for artists of all skill levels. Offering a modern interface and a comprehensive suite of tools, it facilitates everything from quick sketches to detailed illustrations, with features like layer support, customizable brushes, and community integration.

Livebrush is a unique and innovative drawing application that leverages vector technology to create dynamic and expressive brush strokes. Originally built on the Adobe AIR platform, it offered artists a fluid and interactive way to generate artwork with complex textures and animations, moving beyond static lines.

MediBang Paint is a feature-rich, free digital painting and comic creation software available across multiple platforms. It provides a comprehensive toolkit for artists of all levels, from sketching and illustration to manga and comic production.