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.
GoodGantt - The best Gantt chart for Trello®
Planyway - Visual project management for Jira and Trello: manage resources, build project roadmaps, use time tracking.
Gantt - Create beautiful Gantt charts
Wiplo - The easiest way to organize and run your business workflows.
Gantt Charts for Zenkit - Track & manage complex projects with a Gantt chart in Zenkit