DiscoverOrg - DiscoverOrg is an IT sales intelligence platform providing technology marketers access to data, IT org charts, and real time projects.
Google Contacts - Google Contacts is Google's contact management tool that is available in its free email service Gmail, as a standalone service, and as a part of Google's business-oriented suite of web apps Google Apps.
Clearbit - Clearbit provides Business Intelligence APIs
Apple Contacts App - Access and edit your contacts from personal, business, and other accounts with the Contacts app.
Datanyze - The sales prospecting tool powered by technology data
Windows Contacts - Windows has many extraordinary organizers, and in the event that you include distributed storage, then you presumably have more.