I wanted to include a cobblestone-like material in my collection, but I wanted to put a spin on it to move it away from the classic cobblestones material. I settled on creating the kind of smooth polished cobble floor you might find inside a medieval hovel. The graph has plenty of variation, you don't even need to include the stones at all if you don't want as it has a simple dirt base. Exported separately this can create variants perfect for setting-up blend materials. Along with the cobbles I included some shards of pottery and other detritus you might expect in a humble medieval dwelling.
It is part of my Medieval themed Signature Collection for Substance Source which I had the pleasure of working on with the awesome people of the Substance Source team over at Adobe. I set myself a few goals for the set. The most important of which was thorough customisability of each material, I wanted each substance in the collection to have numerous parameters with variations of the main graph could easily be created to give the user a lot of flexibility to customise each material to the needs of their specific projects.
https://magazine.substance3d.com/substance-source-mark-foremans-medieval-world/