There's a much easier solution: the vast majority of legit auto-generated email will have a "List-Unsubscribe" MIME header. I filter based on that header into a

There's a much easier solution: the vast majority of legit auto-generated email will have a "List-Unsubscribe" MIME header. I filter based on that header into a 'Bulk' folder. There are some exceptions, e.g. emails that go via the Drip service, but given limited number of automated email services you can probably catch 99% of emails with a few rules, rather than machine learning.