draw.io - Online diagramming application
Blinkist - Key insights from 6,000+ bestselling books and podcasts
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.
Sipreads - Takeaways from the best books, for free 📕⚡
PlantUML - PlantUML is an open-source tool that uses simple textual descriptions to draw UML diagrams.
12min APP - Free reading app for summaries of nonfiction books.