Numlooker - Numlooker is a web-based tool that is used to reverse the phone number that you have received.
Truecaller - Find a person by a name or phone number worldwide for free using Truecaller.
Rap Sheet Reverse Caller ID - Rap Sheet Reverse Caller ID is an application that provides you the option to search the information about unknown numbers.
CallApp - Free Caller ID & Call Blocker app that allows mobile users to block phone calls, identify calls, blacklist unwanted callers and much more.
NumLookup - NumLookup is a web-based platform that helps you to get information about a person by providing a phone number.
CallerSmart - CallerSmart is an application that is basically used for the purpose of looking up mystery phone numbers for free.