Need help Identifying a brush/effect in Photoshop

I love the effects marked in red used in this wallpaper, though I can't find a specific name for the style. Is it fog? Clouds? Smoke? And where would you get brushes to make something like this?

Any help would be appreciated.

Great design resource

100 Things Every Designer Needs to Know About People (Voices That Matter) Submitted March 13, 2018 at 02:01PM by AutopsyGremlin http://ift.tt/2Go0Ph0