Pintask - Pintask is the most customizable Kanban board.
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.
TaskBoard - A Kanban-inspired app for keeping track of things that need to get done.
Planyway - Visual project management for Jira and Trello: manage resources, build project roadmaps, use time tracking.
buckets.co - Feature rich kanban board collaboration platform.
Corrello - Dashboards for agile teams using Trello