Zenkit - Zenkit is the home you always wanted for your ideas, your projects, your business.
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.
Airtable - Airtable works like a spreadsheet but gives you the power of a database to organize anything. Sign up for free.
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.
SquidHub - SquidHub is a simple and intuitive productivity app for teams. Get the job done - for free! - Todo list, Messages, and File sharing
Basecamp - A simple and elegant project management system.