CircleBack - Contact sync application.
BusyContacts - BusyContacts is a contact manager for macOS.
Cisdem ContactsMate 4.2.0 - Cisdem ContactsMate: Sync, Create, find, manage, group, fix, and export your Contacts. Try it now!
Apple Contacts App - Access and edit your contacts from personal, business, and other accounts with the Contacts app.
Google Contacts - Google Contacts is Google's contact management tool that is available in its free email service Gmail, as a standalone service, and as a part of Google's business-oriented suite of web apps Google Apps.
Windows Contacts - Windows has many extraordinary organizers, and in the event that you include distributed storage, then you presumably have more.