I made these set of renders I while testing the ZBrush FORM materials pack using the BPR projects-ready included in the pack. All the renders are single pass BPR within ZBrush 4R8.
You can get the ZBrush FORM Materials pack here:
http://www.zbrushguides.com/zbrush-form-materials-pack/
(Use the CYBERMONDAY17 code on check out for a 50% off discount - valid until 01/12/2017)
Hope you guys like it!