GanttPRO - GanttPRO is online Gantt chart software for project management. CEOs, project managers, and teams use it every day to solve project management challenges.
draw.io - Online diagramming application
Instagantt - Instagantt is a powerful and intuitive Gantt chart tool to enable teams to plan, manage and visualize their projects easily. Manage your schedules, tasks, timelines, and workload like a Pro. Try it for free.
LucidChart - LucidChart is the missing link in online productivity suites. LucidChart allows users to create, collaborate on, and publish attractive flowcharts and other diagrams from a web browser.
DHTMLX Suite - DHTMLX Suite offers JavaScript UI library for building cross-browser web and mobile applications.
PlantUML - PlantUML is an open-source tool that uses simple textual descriptions to draw UML diagrams.