If you have a Wacom-style graphic tablet and you need a simple and distraction-free painting program, MyPaint seems like it could be a really good fit.
The developer, Martin Renold, says it's a "fast and dead-simple painting app for artists" and I can certainly appreciate the ease of use to it. Very handy for doing any kind of art really. Perhaps if you're in the mood for some sketching, mockups or you're designing art for a game it's pretty sweet.
A big new version is currently in testing, with a Beta that was released back in December. This brings with it great AppImage support to run it (hopefully) out of the box on any modern Linux distribution, along with tons of new features for artists like Spectral Paint/Pigment layer and brush mode, Linear blending for non-pigment layers and brush modes, Smudge enhancements, Fullscreen improvements, "fake inputs" for pressure and barrel rotation (allowing on-the-fly expressive adjustments to your brush even while using a mouse) and loads more.
Artwork: "Pinguins" by Yumemi-chan
MyPaint Feature Highlight:
- Infinite canvas
- Extremely configurable brushes
- Distraction-free fullscreen mode
- Extensive graphic tablet support
- Speed, simplicity, and expressiveness
- Realistic paint-like pigment model
- 15 bit Rec 709 linear RGB colorspace
- Brush settings stored with each stroke on the canvas
- Layers, various modes, and layer groups
Hat tip to dpanter.