There are unsubscribe headers that are used by mail user agents like mutt to unsubscribe from mailing list managers like mailman.

These are "scanner-proof" so far but support in clients like Outlook or Gmail is non-existent.

I'll try unsubscribing once if it looks like a legitimate org, like someone I actually did business with but didn't expect them to email me. After that, it's going to the junk box to train the server what spam looks like.