I've been messing around with using Alphas to model a bit quicker for large scenes (instead of making a high poly and low poly model and baking), and while I tried to use my own for a while, I found some free ones online that are absolutely AMAZING. They have perfect gradients, they have perfect grey values, and so much…
In addition to zbrush you can use your modeling package to make a high poly which you bake down to a plane, or substance designer or equivalent sort of like you would photoshop.