Skype for Slack - Move your slack discussions to a group skype call
Phonebot - Make phone calls from within a Slack channel
Aircall Now - Make voice calls inside Intercom Messenger 📞💬
Luno - Money, reinvented
HandsFree 2 - Call and SMS in Mac using your Android phone via Bluetooth
HideMyFaceTime - Stop watching your own face during FaceTime calls.