draw.io - Online diagramming application
Midnight Commander - GNU Midnight Commander is a visual file manager, licensed under GNU General Public License and...
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.
fman - An unexpected gift. January 07, 2018 by Michael. One of the nice things that happened last week was an fman user writing in to say that 1) fman "is THE BEST SOFTWARE" (sic). And that 2) he would like to send me a $50 tip.
PlantUML - PlantUML is an open-source tool that uses simple textual descriptions to draw UML diagrams.
Krusader - Krusader is an advanced twin panel (commander style) file manager for KDE and other desktops in the *nix world, similar to Midnight or Total Commander.Get your copy of the Krusader .