Ink and bleach. I use ink to show shadow and painted bleach to show light.
I have a bunch of 'stuff' that I've collected, ribbons, yarns, etc. - but have not done any of that yet.
I also want to incorporate the aluminum shavings that my husband makes when he mills aluminum. Not sure how I would do that though as they're swirlly bits of really sharp metal that would catch on everything. I'll figure something out someday when I have a design in my head that screams for bright shiny swirlly things I guess.