Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:4351190.

These are a few ingots that I've sized for approximately 1Kg of the material. No considerations were made for material shrinkage, so if you use these as a mold for a metal foundry you'll want to verify the weights after casting and either adjust the size of the models accordingly or shave off excess so that it hits the desired mass.

I plan on working on more, but this first series has Aluminum, Copper, Lead, and Osmium because of the large differences in volumes of those materials to make one kilogram.