Aha - Aha! is the new way to create visual product roadmaps. Web-based product management tools and roadmapping software for agile product managers.
draw.io - Online diagramming application
ProductPlan - Cloud-based product roadmap software solution
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.
Roadmunk - Create beautiful product roadmaps quickly. Drag & Drop functionality. Export your roadmaps into formats such as: PPT, PNG & URL. Start for free today.
PlantUML - PlantUML is an open-source tool that uses simple textual descriptions to draw UML diagrams.