You're asking what are the cottage industries? Places you won't think to look. Things that may be distasteful. Vtubers are an example of a recently-commercializ

You're asking what are the cottage industries? Places you won't think to look. Things that may be distasteful. Vtubers are an example of a recently-commercialized idea. Look for stuff that's just getting going. The frustrating part is that billions in investment money is performing the same search, and so these ideas don't remain small for long anymore, before they get bootstrapped to their "too big to enter easily but too small/young to solve hard problems" phase by people looking for quick returns.