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.
Hive - Seamless project management and collaboration for your team.
TaskBoard - A Kanban-inspired app for keeping track of things that need to get done.
Sup! Standup Bot - The complete stand-up and follow-up bot
Pintask - Pintask is the most customizable Kanban board.
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.