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.
DeltaSalesApp - Field Sales Force Automation & Field Force Tracking Software
FullContact Card Reader - Automagically scan biz cards into LinkedIn/Gmail contacts
Smart Service - Smart Service's QuickBooks integration makes it the ultimate scheduling and dispatch software for HVAC, plumbing, pest control, and other service industries.
Nextcloud Contacts - The Nextcloud contacts app is a user interface for Nextcloud's CardDAV server.
Service Cloud Field Service - Service Cloud Field Service is a cloud-based field service solution designed to initiate customer service activities from anywhere.