Looking for unubtanium part ideas

As many know I reverse engineer and manufactur unubtanium parts.

Parts that the aftermarket doesn't make.

Usually I stumble on a needed part when someone asks "does anyone make this part"

I figured I would reach out and ask....

Does anyone know if a part that is not reproduced, that you would like to see reproduced?

It can be metal or plastic.

If you have a sample (can be rusted or broken) that I can use to measure from, that would be great.

Let me know your ideas.
I was just thinking about one today but damn if I can think of it now. I'll get back to ya.