CallApp is a Free Caller ID and Call Blocker app that allows mobile users to block phone calls, identify telemarketing calls, record phone calls, blacklist unwanted callers and much more. CallApp is one of the most comprehensive caller ID apps with the ability to identify over a billion unknown callers and update your contacts with full info from social media platforms.
Truecaller - Find a person by a name or phone number worldwide for free using Truecaller.
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.
WhosCall - WhosCall is a reliable caller ID app whose popularity has led to its adoption by many users including international media. You can now manage the numbers calling you regardless of whether they are part of your contact list or not... read more.
FullContact Card Reader - Automagically scan biz cards into LinkedIn/Gmail contacts
CallerSmart - CallerSmart is an application that is basically used for the purpose of looking up mystery phone numbers for free.
Eyecon - Download Eyecon for free to improve your Android or iPhone phone dialer for more beautiful contacts and better communication.