Slack - A messaging app for teams who see through the Earth!
Missive - Team communication app now supporting FB, Twitter & SMS
Quip Chat Rooms - Real-time chat with your team
Spike - Spike solves businesses' communication chaos by bringing together email, team chat, collaborative docs, and meetings, into one feed.
Jive Chime - Real-time messaging for your team
Mailtrim - Email lives forever!. Reinvigorate your emailing experience with the best free email client, the Mailtrim