A collection of video tutorials for advanced users. (Advanced just means you already feel like you know the basics and would like to get into some more detail, you really don’t need to be a professional to follow these)
Note that I personally watched every single video on this list and only added videos that I personally find instructive and well-produced.
Zbrush Sculpting Tutorial - White Walker from Game of Thrones HD
Zbrush Polypaint Tutorial - An Introduction and Basics HD by 3dmotive
Zbrush Hardsurface Techniques part 1
How to Sculpt Hair in ZBrush Tutorial HD
Make braided rope in Zbrush
Making an Eye in Zbrush and Rendering
Zbrush Sculpting #6 - Rock Sculpting - Part 1
ZBrush Detailing Clothes - Select Polygroups by UV + NoiseMaker
In depth Fibermesh tutorial Zbrush 2018
#AskZBrush - "How can you create a Toon Shade look in ZBrush?"
FSQT - Sculpting, PolyPainting, & Rendering Eyes in ZBrush 4R8