diagrams.net (formerly called Draw.io) is a completely free, open-source, cross-platform and stand-alone flowchart drawing application that can be used as a browser-based web application, desktop application and plug-in for some other software. That's to say, you can use its web edition directly in a web browser (no registration required, no limitations, no catches), or use its desktop edition offline under Windows, Mac or Linux OS.

LANState is a visual network mapping, monitoring and managing software specially designed for network manager or administrator, developed by 10-Strike Software from Russia. It can creates an interactive map for your network from which you are able to view the status of all connected devices in real time. At the same time, it will monitor all shared resources and communications within the network, and inform you (via e-mail, SMS, or sound notifications) when various events occur.