Here's a drop that is currently at 88k revenue for massdrop: https://www.massdrop.com/buy/massdrop-x-redsuns-gmk-red-samu...
638 purchases @ 139.99/set
Somebody has dropped 1k on a single custom made key on the secondary market. https://www.reddit.com/r/MechanicalKeyboards/wiki/keyboard_t...
The gaming market has produced all sorts of hobbyist businesses, and that's a market actually big enough to see a few potentially billion dollar businesses. I'm not entirely sure whether something like DXRacer[0] would fall into line of a hobbyist/enthusiast business but it feels like it should to me (and I'm mentioning it because it feels like a larger sort of hobbyist business). It's definitely in that realm in terms of having a pretty specific target market and a relatively higher price point.