Cardhop - The Mac contacts app you'll want to use.
Affinity - Relationship Intelligence, Reimagined
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.
Zapflow - Zapflow is a cloud-based tool for professional investors to manage their deal flows.
Contalist - The contact app for professionals and small businesses
Folk - The next generation contact manager