Sigma File Manager - Sigma File Manager is a free, open-source, quickly evolving, modern file manager (explorer / finder) app for Windows and Linux.
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.
Webuzo - Webuzo Application Manager
draw.io - Online diagramming application
cPanel - With its first-class support and rich feature set, cPanel & WHM has been the web hosting industry's most reliable, intuitive control panel since 1997.
PlantUML - PlantUML is an open-source tool that uses simple textual descriptions to draw UML diagrams.