OnePager Pro for Microsoft Project - OnePager Pro builds Gantt charts, timelines and multi-project reports using data from Microsoft Project, Project Online, and Project Server.
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.
Ganttify - Ganttify is a gantt chart software for visualization of activities and bottlenecks in a project.
GoodGantt - The best Gantt chart for Trello®
Office Timeline - Make impressive PowerPoint timelines with just a few clicks.
Paws for Trello - The best way to use Trello on your desktop