Those were the good old days. Managing the reputation of authenticated sending services took care of most of that stream. I enjoy deleting the thousand or so spams a week Google filters for me. (Did Apple ever figure this out btw? Apple's spam-incompetence has been indisputable evidence that they are dying on the net.)
Now my spam stream is dominated by "legitimate" spam. It looks a lot like my mailbox used to look, back when we had post offices and home delivery. It's full of junk mail from political parties, non-profits, and companies who can somehow claim I've done business with them - in some alternate timeline.
Google won't block this spam stream for me. (Yet.) For the moment, however, these "real" companies use persistent domain names. So I can use old-fashioned domain blacklists on them.
At home I block everything related to the political parties who are interested in me. At work it's all corporate. My current blacklist is below with noteworthy domains in bold 
I have some sympathy for the marketing departments of these companies. That's why I have a proposal.
Authenticate your email with a digitally signed "DonationPaid" (signing authority TBD). This means every email sent donates 30 cents to an approved charity, something like CARE.ORG.
I promise not to blacklist those.
 Current corporate blacklist