Cardhop - The Mac contacts app you'll want to use.
Mailbird - Mailbird is the best email client for Windows 7, 8 and 10
The Contact Guru - Managing your contact list so you don't have to
GrexIt - Manage Tasks, Customer Support and Sales right from your Gmail inbox. Turn your Gmail into a powerful collaboration tool.
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.
New Gmail - The new version of Gmail web