What metals can be worn in piercings for people who are allergic to gold and silver?

It's just I am allergic to silver, gold and am not sure what else.

I can definitely wear white gold but I can't seem to find any types of earrings that I want in it.

I am looking for colourful studs for my ears, possibly not diamonds.

I think i can wear titanium too.

Also, If anyone has heard of bioplast I want to know if it's safe because some websites say it has not been properly tested and if they make earrings in it?

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