Sidekick by Hubspot - Customer insight integrated with your email tools.
Truecaller - Find a person by a name or phone number worldwide for free using Truecaller.
Sansan - Sansan provides a internal contact sharing service for companies.
CallApp - Free Caller ID & Call Blocker app that allows mobile users to block phone calls, identify calls, blacklist unwanted callers and much more.
HiHello - Exchange contacts, seamlessly.
CallerSmart - CallerSmart is an application that is basically used for the purpose of looking up mystery phone numbers for free.