Todoist - Todoist is a to-do list that helps you get organized, at work and in life.
RingCentral - RingCentral is the leading provider of cloud-based communications and collaboration solutions for small business and enterprise companies
Todo.txt - Track your tasks and projects in a plain text file, todo.txt. A todo.
Dialpad - Switch is a cloud-based phone system built for Google Apps users.
EssentialPIM - EssentialPIM is a free Personal Information Manager that keeps up with the times and lets you manage appointments, tasks, notes, contacts, password entries and email messages across multiple devices and cloud applications.
Aircall - Aircall is a call center software of a new generation designed for fast growing companies. Setup instantly and integrates to your CRMs