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.

CAMPR - Open source project management tool with 16 modules

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.

Confleo - Confleo is an all-in-one project management and CRM tool that allows you to create and manage multiple projects, assign multiple users within it, create stunning invoices for your clients and even accept payments from them through in-built payment g…

Jira - The #1 software development tool used by agile teams. Jira Software is built for every member of your software team to plan, track, and release great software.

Basecamp - A simple and elegant project management system.