Skype for Slack - Move your slack discussions to a group skype call
TextNow - TextNow is a mobile virtual network operator (MVNO) that provides a free phone service to users by using other cellular networks coverage.
Aircall Now - Make voice calls inside Intercom Messenger 📞💬
TextMe - TextMe is a free calls and messaging application at both local and international levels.
Calls on Slack - Make voice calls in Slack
Talk360 - Talk360 is a best-in-class communication utility that offers a convenient way to connect with loved ones globally.