Are there any traditional Materials (not MatCaps) available, either individually or in “Packs”? Free or commercial?
I’m looking for more “canned” materials that can be lit by hand, and that have some of the (many) parameters pre-set.
Thanks! 
You could take a look at the MaterialPack from a long time back:
MaterialPack 2
I suggest you unzip the file to your Desktop, then unzip the MaterialPack2Data zip that’s inside and copy the MaterialPack2Data folder that you’ll get to the ZBrush 4R4/ZMaterials folder. The materials will then show up under the Materials tab in Lightbox.
(Although there is a ‘loader’ included in the zip I wouldn’t use it as there may be issues using such an old zsript with the latest version of ZBrush.)
Note also that many of these materials will require a Best Render in order to see the effects. If you are using BPR then you can do the Best Render first and follow immediately with the BPR. You should then get the best of both worlds.
Marcus, Thank You! I found an earlier reference to this Pack (I think) but the link was broken. I appreciate the installation tips, as well: Makes sense. Thanks for all the effort!