I've been asked by Shapeways to give them a plug, and being an accommodating fellow who has used them in the past, here it is!
Shapeways is a 3-D printing company that makes all sorts of things based on designs others enter. As miniatures gamers, there's a lot on offer there. I personally have used them (through the designer CustomMinis, who has a ton of 40k useful designs) for shoulder pads for both the Space Sharks and Sons of Taurus. If I end up expanding the Space Sharks I will probably end up getting the door set pictured above, as FW has dropped the Badab War ball and even stopped making their Carcharodon transfers. Boo. If you have a custom chapter or just want some variety in pads, check them out. I expect you'll be able to find something you can work with.
The interface and searchability still leave a bit to be desired, though it does look like it has improved since I first scrolled through page after page to find what I was interested in. Some examples of things folks might find interesting below:
Want a BFG cruiser? (from GrimDarkBits)
Or some things for X-Wing games? (from Mel_Miniatures)
Some teeny weapons for those Hot Wheels cars you're converting for your Fury Road games? (by swinks)
How about an interesting portal glyph marker for those daemons? (by dashleysmith)
Or maybe you have been looking for the right hats for your Lego Napoleonics army? (by woody64)
Check them out, poke around and I'm pretty sure you'll find something interesting and even useful!