jmousey
168
I suggest adding palladium to the list
While not so popular these days, I do recall Cartier making a number of models available in palladium - Santos, Cle and Pasha come to mind. I think this material was also used by Parmigiani and MB&F.
Also, this might be technicality, but should white gold be separated into rhodium-plated white gold and gray gold? I think some people might actually like the warmer color of aged rhodium-plated white gold, while others might just find it off putting and only chose gray gold.