Truecaller - Find a person by a name or phone number worldwide for free using Truecaller.
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.
CallApp - Free Caller ID & Call Blocker app that allows mobile users to block phone calls, identify calls, blacklist unwanted callers and much more.
ZabaSearch - Find people free with Zabasearch directory engine that includes free people search, reverse phone number lookup, address lookup, and more.
CallerSmart - CallerSmart is an application that is basically used for the purpose of looking up mystery phone numbers for free.
Number Checker. All World - Check the telephone number to identify the country, state, region, city, mobile operator.