Trello - Infinitely flexible. Incredibly easy to use. Great mobile apps. It's free. Trello keeps track of everything, from the big picture to the minute details.

AirSend - Connect with People to get work done. Have conversations, share files, complete tasks, and get work done in one space.

Todoist - Todoist is a to-do list that helps you get organized, at work and in life.

Twake - Be more productive with Twake : the collaborative work platform to organize and manage all your projects on a single platform.

Asana - Asana project management is an effort to re-imagine how we work together, through modern productivity software. Fast and versatile, Asana helps individuals and groups get more done.

Slack - A messaging app for teams who see through the Earth!