Skype for Slack - Move your slack discussions to a group skype call
Missive - Team communication app now supporting FB, Twitter & SMS
Aircall Now - Make voice calls inside Intercom Messenger 📞💬
Spike - Spike solves businesses' communication chaos by bringing together email, team chat, collaborative docs, and meetings, into one feed.
Calls on Slack - Make voice calls in Slack
Mailtrim - Email lives forever!. Reinvigorate your emailing experience with the best free email client, the Mailtrim