Truecaller - Find a person by a name or phone number worldwide for free using Truecaller.
Clearbit - Clearbit provides Business Intelligence APIs
CallApp - Free Caller ID & Call Blocker app that allows mobile users to block phone calls, identify calls, blacklist unwanted callers and much more.
ZoomInfo - ZoomInfo is a B2B database providing detailed business information on people and companies.
CallerSmart - CallerSmart is an application that is basically used for the purpose of looking up mystery phone numbers for free.
InsideView - InsideView aggregates and curates all the company and contact data, news and social insights, and professional connections you need to do business better.