I think you need to limit your scope a bit. A 'side project' could be anything. If you want meaningful responses, you need to give enough info (platform, language, tech stack, etc.) so we get a decent idea if our own project might fit your situation.

You're right, I am unfocused. What would be ideal for me is something in the Python/data/backend world in a fun subject area. But that's pretty narrow and another part of me wants to see many options so as to possibly surface something outside my comfort zone or something I'd never have thought of. I'm just looking for something non-traditional to do next and maybe it's unrealistic that some perfect idea will jump out at me.