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.
Ziflow - Online Proofing software from Ziflow keeps teams connected and collaborating by providing a single source of truth for creative review and approval.
Todoist - Todoist is a to-do list that helps you get organized, at work and in life.
PageProof - Online proofing of anything and everything, made simple. Streamline feedback for easy collaboration, secure workflows, and faster approvals. PageProof. The smarter way to review.
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.
Workgroups DaVinci - Project management and workflow automation software for marketing and creative teams.