I've been thinking quite a bit about this lately and I decided that I should make a post. Most people on this sub I'm assuming have extra keycaps laying around that they don't use, hell most people on here have multiple keyboards so I wouldn't be surprised if they had 1000+ extra keycaps. For me, I use a Poker II and I've only bought 2 more sets for it, leaving me with about 200 extra keys that I literally don't even need (FN keys, numpad etc). I would LOVE to be able to trade these with other people because I'm doing nothing with them and they're pretty cool caps (doubleshot, 2 colors).
My idea is that someone with the resources, creates a keycap "bank", preferably someone who already has a lot of keycaps to begin with, someone who manufactures them. Essentially, people would be able to trade in their extra keycaps in exchange for other caps that people have traded in. Caps would have a value that you can trade for, always favoring the business so they always get more caps. If they have the resources they could sort these caps and keep track of their inventory etc. They can even sell these keys to make a profit off of them.
Would anyone be interested in this? Personally I feel like it would thrive. Imagine trading in a couple hundred random keys for a few rare novelty keys!