Slowly working on my dragon because I can only work for about half an hour before I need to take a break due to my elbow/shoulder, but he will be done soon hopefully.
There are brushes and alphas that you can use, even make your own that will add textures to the mesh, but with this I am just going to add texture myself because I want the scales to be random. I didn't like how the pre-made textures looked on this model, too uniform and easy to pick out the pattern. You can probably change the settings so the textures are random, but I need to look up how to do that. There is so much you can do with ZBrush that its going to take awhile to learn it all.