How do you gather information about malicious infrastructure?

I'm working on a cyber security SaaS platform that helps cyber security researchers gather information about malicious infrastructure - download malware, scan ports, fetch SSL certificates, etc.

I want to gather some information about how other people do these tasks without my application so that I can build it to help the most people possible. I know how I used to do it (TL;DR - it was a pain in the ass) but I don't want to assume my method was the typical one.