Skype for Slack - Move your slack discussions to a group skype call
Speek - Record and share voice notes on the fly
Aircall Now - Make voice calls inside Intercom Messenger 📞💬
Noor - Chat like you're in the office together
Slack - A messaging app for teams who see through the Earth!
Voicl - With Voicl you can easily embed voice notes onto your website.