Quick question about Scammers

How do scammers robocall/find your email address? Just wondering

Enumerating numbers, data breaches, scraping emails, etc

They buy lists of people from shady folks. Many Facebook groups openly sell lists.

Yes, I know this, but I think they are asking where the shady people get the lists from.

Stolen from business like Target, AT&T erc. Also other scammers who have scammed victims.
I am member of various Facebook groups and see scammers selling.