Black watercolor paper--heard of it? Tried it? I have some (because I have an art supply addiction, you see) but I've struggled to use it over the past year or so I've owned it.
Recently I found a way to use both my black watercolor paper and another supply that was gathering dust: my mica powders. I mixed up a small batch of 5 different interference mica powders with gum arabic to make my own custom watercolor paint that looks great on black paper!
Interference paint changes colors as you move it around in light. It's another unusual supply that's pretty limited in its use. But with the help of that black watercolor paper, I made some sparkly, shiny little paintings that make my magpie heart happy!