ZBrush Video Tutorial Resource (Patreon)

I strongly recommend this video series by Steve James. I'm quite picky with videos, but he does a great job. 

https://www.youtube.com/watch?v=tb5z2AOxaCQ&feature=youtu.be

Good for beginners, and those looking to polish their skills.

He covers basic shapes, workflow, and all the elements of the head.

Maybe I'll make my own video series one day~