Missive - Team communication app now supporting FB, Twitter & SMS
Loop Email - Emailing for teams: Organize your Inbox into channels 💌
Slack for Mobile - Rebuilt from the ground up
Thunderbird - Thunderbird is a free email application that's easy to set up and customize - and it's loaded with great features!
Front - multi-channel inbox service for collaborative teams
Pie.video - Make and watch 360 videos with your iPhone