HeySpace - HeySpace is the only free task and simple project management software with communication and collaboration feature.
Invision - Prototyping and collaboration for design teams
Slack - A messaging app for teams who see through the Earth!
Marvel - Turn sketches, mockups and designs into web, iPhone, iOS, Android and Apple Watch app prototypes.
Skarpline - Skarpline provides centralized enterprise messaging, link sharing and file management to improve productivity.
Axure RP - The prototyping and specification software used by 87% of the Fortune 100. Beyond mockups, design interactive prototypes for business solutions, websites, and applications.