Truecaller - Find a person by a name or phone number worldwide for free using Truecaller.
Kontact - Kontact is the integrated Personal Information Manager of KDE.
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.
Nextcloud Contacts - The Nextcloud contacts app is a user interface for Nextcloud's CardDAV server.
FullContact Card Reader - Automagically scan biz cards into LinkedIn/Gmail contacts
Eyecon - Download Eyecon for free to improve your Android or iPhone phone dialer for more beautiful contacts and better communication.