LTSP - The Linux Terminal Server Project adds thin-client support to Linux servers.
Nessus - Nessus Professional is a security platform designed for businesses who want to protect the security of themselves, their clients, and their customers.
Thinstation - Thinstation is a basic and small, yet very powerful, open source thin client operating system...
Tenable.io - Tenable.io Cyber Exposure platform helps to protect any asset on any computing platform and eliminate blind spots.
Nakama - Nakama is an open-source distributed social and realtime server for games and apps.
AlienVault USM (from AT&T Cybersecurity) - AlienVault USM Anywhere delivers powerful threat detection, incident response, and compliance management for cloud, on-premises, and hybrid environments.