Thinking about starting a #Mastodon instance, but not sure about a theme to build on.

I live in #Chicago - are instances based around large cities or locations a thing?

I generally work in and know #tech, but we already have an instance or three of those. Less generally I'm mostly in the #Apple neck of the woods, could that be a thing?

I love games, but we already have elekk.xyz and others covering the (board) game space.

Thoughts? Advice?