Skype for Slack - Move your slack discussions to a group skype call
Mailtrim - Email lives forever!. Reinvigorate your emailing experience with the best free email client, the Mailtrim
Aircall Now - Make voice calls inside Intercom Messenger 📞💬
Loop Email - Emailing for teams: Organize your Inbox into channels 💌
Calls on Slack - Make voice calls in Slack
Missive - Team communication app now supporting FB, Twitter & SMS