Here is where you can buy glass stands for your spheres. We were excited to buy these as many people did not like the metal stands for their spheres.
While the indent will handle under 40mm diameter balls, they seem to hug the 40-50mm best. The glass is not deep enough to hold a sphere securely like the metal stands to. However they do work well at stopping a sphere from rolling off the table. They will not suit eggs at all.
AS we bought a lot we reduced the price. And there is an extra discount for bulk if you buy glass stands for your spheres or maybe for others.