What markets have more interesting breadth of coverage + have decent betting limits? I had the impression cftc or sec limit this to avoid become a regulated security.
If you want intellectual engagement and don't prioritize money, then you can find markets on any topics. Which is why I suggested gjopen.com, and if you are good enough then they will try to recruit you to their analytics platform.
But, yes, politics via PredictIt has been the standard CFTC-approved platform. They're rumored to be working on a more general uncapped platform due to competition from Kalshi (next paragraph).
A new YC startup, Kalshi.com, got CFTC approval for uncapped markets with no topic limitations. They only got up and running last year, so often the markets don't play as large with no betting limits even compared to PredictIt. We're hoping they get momentum, but they could be ahead of their time and give up before more widespread adoption takes off.
There is also Polymarkets.com, but it's trying to operate the markets via blockchain. It's often not the greatest user experience for that reason, but they get more leeway on markets and are uncapped.
It's not so much the caps that are a concern to me than the fact that these platforms haven't been around for a long time. There's no guarantee they will continue to always exist and also be as lucrative. As more money enters I'd expect ROIs to decrease and for it to take more capital to make the same amount of money.
I prefer it more as a side hobby than something I have to do every day. It can be fun, but it's missing the satisfaction of building things or delivering something of value to customers that I'd get if I were still working for a company coding.