GrafX2: a bitmap paint program inspired by Deluxe Paint

GrafX2 is a bitmap paint program inspired by the Amiga programs iDeluxe Paint and Brilliance. Specialized in 256-color drawing, it includes a very large number of tools and effects that make it particularly suitable for pixel art, game graphics, and generally any detailed graphics painted with a mouse.The program is mostly developed on Haiku, Linux and Windows, but is also portable on many other platforms.

This program has been around since the early '90s, and runs, among other platforms, on Haiku today. Amazing.