Skype for Slack - Move your slack discussions to a group skype call
EasyCall Phone Call Center - Instantly provide voice customer support through phone calls.
Calls on Slack - Make voice calls in Slack
Voiptime Cloud Call Center - Cloud call center & telemarketing solution
Pingly - Your communication hub — Email, text & voice in one app
Daily.co for Intercom - Free video calls & screen shares embedded in Intercom