I have been thinking in terms of a very low coefficient of expansion solid made from powders of ground glass or mixed materials like a mix of sugar, kaolin, and sand, or many similar possibilities. If the powder is fused the part not fused can be washed away by water leaving a fine lattice of fused material. If the lattice is silicon carbide (sugar & sand) it could make a great high temp heating element capable of temps in excess of 2k degrees F. The first question, of course, is the ability to experiment without injuring the Glowforge and the second if a preformulated “card” could be included in the list of available materials.
Has anyone tried anything like this? Raku clays might also be a consideration.
I had a project years ago that I made glass flowers by shaping powdered glass on a mold and firing it in a small oven. and also have some background in Glass and clay formulas. making a glass oven using silicon carbide heating elements is also done, and the commercial controllers are very expensive but I learned of a better way. Of course the smaller the diameter of the silicon carbide the less amps it takes to heat it or higher voltage so in theory anyway, one could make a very nice oven or hot plate with a Hilbert curve shaped piece of silicon carbide.
This is, effectively, how laser sintered 3D printing works:
there’s a lot of complexity to get 3d, but for 2d as you’re describing I think @PrintToLaser has it right, that the biggest issue will be that you’ll get better results with smaller particles, and smaller particles will be the most likely to blow around like mad.