Tack on additional metadata to a material?

Is there a clever way to have additional metadata on a material?

I have a tool that lets a user select from dozens, potentially even hundreds of materials. I’d like those materials to have a title, description, thumbnail, pricing, etc.

It’d be best to store that info in something like an XML file

XML works fine, but if you want to stay “in engine,” I’m assuming you could also use data tables as well.

Don’t know if it counts but adding a physics material does so interesting things.