I'd imagine stuff like SSL certificate expiry monitoring, CT log monitoring, or IP address geolocation / reputation. I assume a handful of fortunes have been m

I'd imagine stuff like SSL certificate expiry monitoring, CT log monitoring, or IP address geolocation / reputation. I assume a handful of fortunes have been made this way. But you're competing with people who can outspend you on Google Ads, have enterprise sales teams, and stuff like that. No free lunch!