Does this count? I designed* a batch of signature items/bottlecap charms. I've yet to memorize the code for decoding additional hints on caches and I got tired of always having to write out the alphabet on whatever scrap of paper I could find, so I made these. I figured maybe other people have the same problem, and I've read that quite a few people out there like to collect signature items, so...best of both worlds? Maybe?
*I know it's a ridiculously simple design, and maybe there was a fast and easy way to go about it, but this was kind of a labor of love for me, so I'm pretty proud of it anyway.