A unique set of brushes that have an oval shape as their tip. The brush tip spacing is wide, so there's spaces in the lines. It makes more sense once you use it yourself. I like to use this brush to do sketches, but you can render with these if you really want to.
This pen actually used to be one of my older pens, but I fiddled around with the settings a bit so that it's more unique.

Both Forest Brushes