HeySpace - HeySpace is the only free task and simple project management software with communication and collaboration feature.
Missive - Team communication app now supporting FB, Twitter & SMS
Rivers IM - Simple, fast & secure team collaboration platform
Spike - Spike solves businesses' communication chaos by bringing together email, team chat, collaborative docs, and meetings, into one feed.
Slack - A messaging app for teams who see through the Earth!
Mailtrim - Email lives forever!. Reinvigorate your emailing experience with the best free email client, the Mailtrim