FullContact Card Reader - Automagically scan biz cards into LinkedIn/Gmail contacts
FullContact - Put the power of full contact information into your web or mobile apps.
Truecaller - Find a person by a name or phone number worldwide for free using Truecaller.
Pipl - The most comprehensive people search. Pipl is the place to find the person behind the email address, social username or phone number.
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.
Evercontact - Your contacts always up to date and automatically with Evercontact.