ThisNumber is an international directory of phone books and U.S. phone number lookup service.
Truecaller - Find a person by a name or phone number worldwide for free using Truecaller.
CallerSmart - CallerSmart is an application that is basically used for the purpose of looking up mystery phone numbers for free.
PhoneGenerator.net - Generate random phone numbers for all countries using the mobile phone generator. These numbers are fake, but they are built using the validations of telephone numbers.
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.
Sync.ME - Search over 1 Billion phone numbers worldwide. Identify unknown phone numbers and block unwanted calls.
Phone.Report - Complete phone number report.