Drawn with Linux MyPaint.
I still haven't found a brush I like as much as the Chibi Paint "watercolor" brush.
There is a kind of a fine balance where a digital brush pulls the paint and where it is just smearing or blurring it.
The ideal brush for me would simultaneously be loading color and pulling it away from an adjacent mark, and actually looking like a brushstroke without obviously or self-consciously imitating physical media.
Most of the "blend" brushes in MyPaint just dissolve, so everything resembles the Photoshop smudge tool, an effect I dislike.
Here I am compensating by crosshatching, so a volume is built up with fine lines of gradually lightening or darkening color.
The Microsoft Paint brushes in the Windows 7+ versions don't have any dissolve function at all -- they are all very "scratchy." I ended up getting my best results with the "colored pencil," which had a softer, semi-transparent line.
It's hard being a primadonna in a world where the digital tools are conceived by engineers. "Hey ottist I made a brush for ya!"