At
graphics-illustrations.com there is a selection of some 50 Hi-Res
Photoshop Brushes sets that are free for commercial use.
You will have to subscribe to the newsletter where we announce new free Photoshop Brushes, and I'd say it worthwhile since those you can use for free in your commercial graphic-design projects.
All Photoshop brushes are created by
bsilvia who is the owner of Graphics-Illustrations.com site.