Brass Plate for Plaque, Where to?

I am looking for a brass plaque(s) about 2x4, or so, with or without a black coating. I have looked on Amazon, but all I can find are plaques with engraving.

Can anyone point me in the right direction where I can purchase the raw product so that I can do the work myself.

Thank you all for your time and support.

It has been quite awhile since I looked but try searching trophy supplies on google

A simple Google search brings up about 10 pages of places. Search blank brass plaque.

A quick search turned up many sources. I randomly selected one.

Good luck

Check McMaster-Carr or SpeedyMetals

Here is another resource. onlinemetals.com