Bronze Foil Style/ Gun Metal Foil Style

You might have missed these sets in the kits section: https://www.digitalscrapbook.com/sheila-reid/kits/vintage-metal-styles-set-01-kit-antique-copper-gold-pewter-bronze-brass-nickel

https://www.digitalscrapbook.com/sheila-reid/kits/vintage-wire-styles-kit-metal-antique-gold-nickel-brass-copper-bronze-burgundy

These foil styles could work with a slight mod to the style's color--easy enough in Photoshop if you apply the layer style and then edit the color overlay or gradients, though I'm not sure what you're using for software: https://www.digitalscrapbook.com/sheila-reid/kits/vintage-heat-embossed-foil-styles-kit-gold-bronze-copper-silver-black

There are also others available off of PixelScrapper. I don't know what their status is for CU stuff, but they should be all right for personal use, at least:
Freebies at Brusheezy... http://www.brusheezy.com/styles/49769-7-antique-steampunk-metal-styles

Also several good ones on this page: http://www.freecreatives.com/styles/photoshop-styles.html, especially this link: http://manoluv.deviantart.com/art/Austere-Photoshop-Layer-Styles-212297925

I'll work on a couple of CU-friendly ones, though--styles are pretty easy for me to come up with.

Also, check out Karry Dempsey's Steampunk kit from the Freebies forum--it might give you a huge head start on that album!
DeviantArt tends to have some great steampunk stuff, too, as well as layer styles galore, though most of them will be personal use, but it sounds like that's what you're looking to make anyway, so it's an option.