I've never looked closely at the default brushes in PS. So I decided to go through the default brushes in CS6, using them to create spheres with values. All examples started with a black sphere and were tinted to get value representations. Some brushes were skipped since they were close to already existing brushes (Hard Round vs Hard Round Pressure Opacity). The only things I manipulated were the opacity and flow settings of each brush.
Some were really hard to work with and not really intended for shading, so results vary