I believe(correct me if I am wrong) that each of the three godmetals that we know about (atium, lerasium, and harmonium) can be alloyed with each of the existing 16 metals for various effects. What do you think they all do in terms of Allomancy, and Feruchemy?
We know that atium and gold show other people's pasts and I believe there is a WoB stating that all Atium alloys had temporal effects allomanticaly.