Isle of the Kakapo (https://www.isleofthekakapo.com/home-isleofthekakapo.html) has released U Spammer..? 1.0.1 for macOS. It a free utility for quickly checking a list of email addresses for suspicious activity based on scoring provided by the stopforumspam.com API [application programming interface].
U Spammer…? requires macOS 10.12 or newer. It’s available at the Mac App Store in the Utilities section and does include optional in-app purchases to support future development.