Tiki-Toki - Tiki-Toki is web-based timeline software for creating beautiful interactive timelines that you can share on the web.
draw.io - Online diagramming application
Aeon Timeline - "The timeline tool for creative thinking. Capture, create and explore ideas."
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.
Sutori - Sutori is the easiest way to create an interactive story collaboratively.
PlantUML - PlantUML is an open-source tool that uses simple textual descriptions to draw UML diagrams.