Simple Poll - The easiest way to create polls in Slack
draw.io - Online diagramming application
GitHub Polls - Polls for GitHub issues and readme
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.
minipoll - Create simple shareable polls in seconds
PlantUML - PlantUML is an open-source tool that uses simple textual descriptions to draw UML diagrams.