ZabaSearch - Find people free with Zabasearch directory engine that includes free people search, reverse phone number lookup, address lookup, and more.
Clearbit - Clearbit provides Business Intelligence APIs
RealPeopleSearch - RealPeopleSearch is a web-based software that allows you to get the basic and public record of the concerned person within a few minutes by providing little information.
ZoomInfo - ZoomInfo is a B2B database providing detailed business information on people and companies.
ThatsThem - ThatsThem is one of the best 100% free personals look locales to tag along since ZabaSearch.
InsideView - InsideView aggregates and curates all the company and contact data, news and social insights, and professional connections you need to do business better.