Imagine running your favorite Windows applications and drivers in an open-source environment you can trust. That's ReactOS. Not just an Open but also a Free operating system.

osquery allows you to easily ask questions about your Linux, Windows, and macOS infrastructure. Whether your goal is intrusion detection, infrastructure reliability, or compliance, osquery gives you the ability to empower and inform a broad set of organizations within your company. osquery gives you the ability to query and log things like running processes, logged in users, password changes, USB devices, firewall exceptions, listening ports, and more.
You can perform ad-hoc queries or schedule them, optionally enable file integrity monitoring and process accounting too

YunoHost is a server operating system aiming to make self-hosting accessible to everyone.

Penetration Testing Linux OS containing tools to test the security of system or a network.

Lucid is a free, open source web desktop, or webOS that lets you:

• Access your media, office documents, and other files anywhere
• Stay up to date with Twitter, RSS feeds, and what's happening on the web
• Create great web applications in ridiculously short amounts of time