The Stalwart mail server allows for that. They call them "spam traps".

Basically, it's a real email address that literally never gets used or referenced anywhere, thus assuring any email received is unsolicited by definition. Stalwart's spam engine uses any such email to help train the spam filter.

I can't imagine that Stalwart is only one implementing such a system.

I've never used Stalwart, but it's the email server I've selected should I decide to do what everyone tells me I shouldn't: run my own server for me, my wife, and the two domains we control. Their documentation is basically a master class in email.