Hello there and sorry for the late reply.
First, I made a Fractal in Fractal Domains through Math, changed the Fractal looks into the 'Dotted' variable.
Then cropped, layered and even rotate some of them. Later I did convert them into Brushes in Photoshop.
But you need a Mac to use Fractal Domains, so that might be an obstacle.
I hope it was somewhat helpful, if not ask and I'll try to help you further.