I've put together a notification system that monitors jobs all over the most popular freelance and hiring platforms. It informs me when someone posts a relevant job request. I filter all the incoming info to get emails about those very rare, most relevant for me, and most lucrative jobs that I want. So the whole thing ends up sending 2-5 emails with job details. When I see something extremely relevant - I contact the person.

I'm actually thinking of creating a SaaS from it and looking for users to interview. Ping me :)