Void
Void is an independently-developed, general-purpose operating system based on the monolithic Linux kernel. It features a hybrid binary/source package management system which allows users to quickly install, update and remove software, or to build software directly from sources with the help of the XBPS source packages collection.
SmartOS
SmartOS is an open-source UNIX-like operating system based on illumos, a community fork of OpenSolaris. It features four technologies - ZFS (a combined file system and logical volume manager), DTrace (a dynamic tracing framework for troubleshooting kernel and application problems), Zones (a lightweight virtualisation solution), KVM and bhyve (two full virtualisation solutions for running a variety of guest operating systems, including Linux, Windows, BSD and Plan9).