Evercontact - Your contacts always up to date and automatically with Evercontact.
GrexIt - Manage Tasks, Customer Support and Sales right from your Gmail inbox. Turn your Gmail into a powerful collaboration tool.
CONTACTBOX - CONTACTBOX combines the simplicity of an address book with effective functions of a CRM system.
Mailor - Shared inbox, team portal and smart notifications
Bigin by Zoho CRM - Pipeline-centric CRM built and priced for small businesses
Airmail for iOS - One of the best Mac email clients, now on iPhone