Trello - Infinitely flexible. Incredibly easy to use. Great mobile apps. It's free. Trello keeps track of everything, from the big picture to the minute details.
Dialpad - Switch is a cloud-based phone system built for Google Apps users.
Notion - All-in-one workspace. One tool for your whole team. Write, plan, and get organized.
RingCentral - RingCentral is the leading provider of cloud-based communications and collaboration solutions for small business and enterprise companies
Slack - A messaging app for teams who see through the Earth!
Aircall - Aircall is a call center software of a new generation designed for fast growing companies. Setup instantly and integrates to your CRMs