avaamo - Simple, Secure Business Messaging
Missive - Team communication app now supporting FB, Twitter & SMS
SupportKit - Embed Zendesk support into your iOS app with 1 line of code
Spike - Spike solves businesses' communication chaos by bringing together email, team chat, collaborative docs, and meetings, into one feed.
Fleep for Business - Simple, open collaboration and chat with admin capabilities
Mailtrim - Email lives forever!. Reinvigorate your emailing experience with the best free email client, the Mailtrim