I often think about how useful a market type thing would be designed specifically for selling and trading single keys from keysets. I often find that when a set doesn’t specifically cover my ortho board that I could cover it myself, I would just have to spend $300 on 5 kits when I only need 48 keys. And as you said, you can often nearly cover two by buying two sets of alphas and one set of mods. A couple people I’ve encountered will be offended at the mere mention of splitting up a kit, though.