Sidekick by Hubspot - Customer insight integrated with your email tools.
Truecaller - Find a person by a name or phone number worldwide for free using Truecaller.
HiHello - Exchange contacts, seamlessly.
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.
Sansan - Sansan provides a internal contact sharing service for companies.
FullContact Card Reader - Automagically scan biz cards into LinkedIn/Gmail contacts