ZBrush - MirrorVisible Script
Fran Picazo has created a script with which you can mirror all visible subtools in ZBrush.
10 Tips for ZBrush
Discover the secrets of a faster workflow in ZBrush with these 10 useful tips.
NanoTile Textures for ZBrush
NanoTile Textures is an unofficial plugin that helps create tiling textures using NanoMeshes in ZBrush.