I’ve created a PDF of unassigned hotkeys for ZBrush which is useful if you want to browse by key assignment & prefer not to overwrite default keys. I couldn’t find this anywhere and just got tired of trying to determine what to use. I hope it is of some use. If there are edits please let me know.
HERE IS THE LINK: https://www.dropbox.com/s/zx0m6lsah06zh83/Assigned%20and%20Unassigned%20Zbrush%20Hotkeys.pdf?dl=0