paid forums - what niches?

[Tozzy]

I was just curious (no, I don't wanna start my own one) what niches paid forums work for?
The only ones that I can see are money making-related forums (e.g. SEO/sports betting etc) but I couldn't come up with anything else.

 

[PHPInjected]

The fitness industry is still really large, especially with all of the 'get fit' campaigns that are out there.