The following brushes can be downloaded for free and be used for both personal and non-commercial usage. You can do what you want with my sculpting brushes, but you are not permitted to resell them. If you have found them useful, then please do share this page with your friends and colleagues.
50 Mixed Blender/ZBrush Brushes
Download all 50 sculpting brushes in a single zip file. There is a Blender file in the zip, but you can also import these into ZBrush or your preferred 3D sculpting application. Each brush is generated as a 2k, 32bit tif file.