Here are a few brushes I enjoy using. I find them extremely helpful and I think you should take a look at a few of them.

1. Cloud brushes by JavierZhX

Love this set , very useful !
Download
Website; Click Here


2. Photoshop Splatter Brushes by ~konakonakona

The wonders of a good splatter brush pack :) This one is my personal favorite !
Download
Website; Click Here

3. Cloud Smudge Brushes by =Noise-Less

You got to have a good smudge brush!!! Its just a need , and this one it the best :)
Download
Website; Click Here