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.
Mocklets - A HTTP-based API simulator to assist parallel development 🛠️
Drupe - Next generation contact manager and dialer.
API List - A collective list of APIs. Build something.
Simple Contacts - Contact lens prescriptions from home
Airbnb Official API - Develop your application for millions of travelers & hosts