Salesforce Data.com - Data.com provides company profiles and contact information across millions of businesses worldwide.

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.

Demografy - Demografy is a SaaS platform that uses AI to predict customer demographics from names. It provides full coverage, accuracy estimate before purchase and work with even masked names enabling privacy and GDPR-compliance.

Apple Contacts App - Access and edit your contacts from personal, business, and other accounts with the Contacts app.

YesData - YesData offers data cleansing and enrichment solutions.

Windows Contacts - Windows has many extraordinary organizers, and in the event that you include distributed storage, then you presumably have more.