Pennywise - Cross-platform application to open any website or media in a floating window
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.
Nibbler - Free tool for testing how good your website is, and what you can do to improve it. Check accessibility, SEO, social media, compliance and more.
draw.io - Online diagramming application
Puzzle - AI-powered content operations platform to streamline content creation
PlantUML - PlantUML is an open-source tool that uses simple textual descriptions to draw UML diagrams.