Kontact - Kontact is the integrated Personal Information Manager of KDE.
Evercontact - Your contacts always up to date and automatically with Evercontact.
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.
CONTACTBOX - CONTACTBOX combines the simplicity of an address book with effective functions of a CRM system.
Kontact - KAddressBook - KAddressBook stores all the personal details of your family, friends and other contacts.
Bigin by Zoho CRM - Pipeline-centric CRM built and priced for small businesses