Dialpad - Switch is a cloud-based phone system built for Google Apps users.
EasyCall Phone Call Center - Instantly provide voice customer support through phone calls.
RingCentral - RingCentral is the leading provider of cloud-based communications and collaboration solutions for small business and enterprise companies
CloudTalk - Work locally, grow globally
CallHub - Predictive Call Center, Voice and Text Broadcasting app
CallKite - Your website’s video call center in just one click.