What is the best metal type to avoid getting a keloid on your piercing?

Since keloids: Are a reaction to the physical trauma of piercing, the best way to avoid a keloid is to not get pierced. The type of metal doesn't matter. However, many people have an allergic reaction to nickel - which is a different thing.

Avoid alloys: Gold and titanium are well tolerated by most. Steel and plated jewelry tends to have alloys that result in a higher incidence of reactions.