A lot of keyrings are actually plated brass. You can always take a good magnet and check them at the local hardware store. Chains for ceiling fans are often brass, and would make good neck chains.

I also have a fish stringer with what look kinda like big safety pins that are made of brass. There are a half dozen of those on a brass chain. Can take those apart and have clips for everything you carry. I've seen them recently in the fishing department of a sportinggoods store. While you're there, just for kicks, walk down the isle where they have the anchors, oarlocks, etc.... All kinds of SS and brass doodads that you'll have uses for.