draw.io - Online diagramming application
RoomForTea - A female-friendly housing network in London, UK.
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.
Travel Diaries - Create your own travel diary to capture your experiences
PlantUML - PlantUML is an open-source tool that uses simple textual descriptions to draw UML diagrams.
mockingbird - Mockingbird helps you you create and share clickable wireframes. Use it to make mockups of your website or application in minutes.