Treehouse - Treehouse is an award-winning online platform that teaches people how to code.
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.
Teachable - Create and sell beautiful online courses with the platform used by the best online entrepreneurs to sell $100m+ to over 4 million students worldwide.
draw.io - Online diagramming application
PowerSchool - PowerSchool provides a K-12 education technology platform for operations, classroom, student growth, and family engagement.
PlantUML - PlantUML is an open-source tool that uses simple textual descriptions to draw UML diagrams.