So I did a little searching to find free design elements that were "for commercial use". This is what I have found so far. Below I have listed images with links to sites where you can download free Photoshop brushes that are allowed to use in your commercial designs. Be sure to thank the artist's.
BE SURE YOU READ THEIR TERMS OF USE ON THEIR PAGES BEFORE USING.
Sometimes people change their mind or have restrictions on the use of their artwork, resources, or files.