People who personally have 100,000 Yahoo accounts because they made them back when you could just pretend to be blind and request the captcha in spoken form, and then fed it into Google's speech to text engine, fed it back in to Yahoo, made the accounts, and who also have a botnet of a million residential IPs and can spin up a bunch of servers to run some scrapers.
The shady SEO people (including the social media account farmers) and the spammers, who seem to always find a way around everything that's put in place against them.