draw.io is a diagramming plugin for Confluence and the #1 rated Confluence add-on since 2013.
Powerful, easy to use and secure diagramming. #1 JIRA diagramming solution
Embed your Google Drive files easily within Confluence using your existing browser authentication. Supports the standard Google Office applications , most standard file types and draw.io files.
PlantUML for Confluence Cloud provides a free PlantUML and Graphviz diagram generation service that stores your text and images directly in your Confluence Cloud instance.