A simple brush with a simple color jitter to make it look more interesting. It was made to be used as a blush brush, but you can use it as you want <3
It is composed by paralel lines and the jitter works with any color, very usefull if you want to give an interesting detail to your art, but it also works in the iris, just as shown in the thumbnail.
It works pretty well with any brush size too!
The other brush I used for the examples is Textured Flat Brush, you can find it in my profile.