ReportedCalls - ReportedCalls helps people search and identify potential spam and scam phone numbers.
FastPeopleSearch - Research people reverse lookup various pieces of information similar.
800 Notes - A place to complain anonymously about a Phone calls received from Bad Company. Consumer Protection.
Spokeo - Spokeo bills itself as the white pages of the internet and provides a platform for anyone to look up publicly available data from online and offline sources. Read more about Spokeo.
Truecaller - Find a person by a name or phone number worldwide for free using Truecaller.
CallApp - Free Caller ID & Call Blocker app that allows mobile users to block phone calls, identify calls, blacklist unwanted callers and much more.