What is a niche hobby of yours that you are fascinated by and would like to share with others?
I'll start. I have recently gotten into 3D printing, and, while incredibly frustrating sometimes, there's nothing more rewarding than getting a perfect print.
Blacksmithing. Something so primal and simple about it. And you get to play with fire. But what I find most satisfying is the ability, once you have a few simple tools, to make any other tools you need. It's like the og 3d printing.