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.

FullContact Card Reader - Automagically scan biz cards into LinkedIn/Gmail contacts

YesData - YesData offers data cleansing and enrichment solutions.

Nextcloud Contacts - The Nextcloud contacts app is a user interface for Nextcloud's CardDAV server.