The Mac contacts app you'll want to use.

Nicolas Bernado
Nicolas BernadoSomeday I'll totally hunt a product. · Written
You could give CardHop a try (21 days free trial on macOS). It gives you an overview of all your contacts of all the accounts you have set up on your Mac. It groups them by account and gives you an idea which contacts are linked to which of your online accounts. I still haven‘t entirely figured out why some contacts show that they are on your Google, others on your exchange and others just show no association at all. But it‘s worth to check out :)