Dingtone - Dingtone is a free call and texting application for making unlimited calls and text messages to any number at the moment registered in any part of the world by any cellular company.
Jenkins - Jenkins is an open-source continuous integration server with 300+ plugins to support all kinds of software development
Textnow.com - It lets you text your friends, aka my only source of happiness
CircleCI - CircleCI gives web developers powerful Continuous Integration and Deployment with easy setup and maintenance.
FluffyChat - Open. Nonprofit. Cute ?
Codeship - Codeship is a fast and secure hosted Continuous Delivery platform that scales with your needs.