Cisdem (www.cisdem.com) has given us ContactsMate 4.2.0 for Mac. It’s an update of the contact management software that will analyze, report, and fix issues with macOS Contacts.
It will also and export the Mac Address Book to different formats for contacts back-up or syncing. Version 4 is compatible with macOS High Sierra.
A demo of ContactsMate is available for download. Registration is $29.99. The app requires macOS 10.11 or higher.