Brushes Deep Dive

I would like a deep dive on Brushes and Smudge brushes. I want to understand the nuts and bolts of the brush settings. To know the difference between a regular brush and a smudge brush. How to create and modify brushes and some guidelines as to what works and what doesn’t. How to use creative brushes (where are they useful, what type of effects do you achieve). How can I use brushes in non traditional ways. For example create a textured background, geometric patterns, designs, use to create abstract images, impressionist, painting, etc..