Apps similar to illumos include Linux Mint, which is free and open source. Other options are Ubuntu, Debian, Fedora and Arch Linux. There's no shortage of Operating Systems like illumos, with more than 100 alternatives for Linux, self-hosting, Windows, Mac and Chrome OS.
Darwin is the Open Source operating system from Apple that forms the basis for Mac OS X, and PureDarwin is a community project to make Darwin more usable (some people think of it as the informal successor to OpenDarwin.
Minoca OS is a general purpose operating system designed specifically for feature-rich embedded devices. It's got all the high-level functionality that you've come to expect from an operating system, but offers it in a fraction of the memory footprint.
Canada
Korora is an installable Fedora Remix Live USB image which aims to provide a complete out of the box experience for new users, including support for multimedia.
BSD-derived desktop OS designed for usability, featuring graphical ports management, GNUstep system configuration, standard tools for daily tasks including email, web browsing, and word processing, supporting multiple licenses like BSD, X.org, and GNUstep.
United States
GeckoLinux is a Linux spin based on the openSUSE distribution, with a focus on polish and out-of-the-box usability on the desktop.
United States
ToaruOS is a completely-from-scratch hobby operating system: bootloader, kernel, drivers, C library, and user space including a composited graphical UI, dynamic linker, syntax-highlighting text editor, network stack, etc.
United States
instantOS is a Manjaro based distro that works out of the box but is still aimed at power users. Everything is lightning fast and works out of the box.
Live bootable linux CD supported by US department of defense, featuring firefox, thunderbird, word processor, and reads USB flash drives.
Pisi Linux; which includes the PiSi package management system, it is an end-user oriented GNU / Linux distribution that aims to provide computer users with great ease of installation, configuration and use and to meet their main desktop needs.
Türkiye
Based in Ottawa, Ontario, Canada, BlackBerry QNX has provided foundational software for many of the world’s mission-critical embedded systems since 1982. From nuclear power plants, surgical robots and class III life-critical medical devices to autonomous vehicles and brands like...
aptosid is an operating system based on the Debian GNU/Linux unstable branch, codenamed sid, and our ISOs hold fast to the core values and the Social Contract of Debian (DFSG).
Germany
EU
Calculate Linux is based on Gentoo that is well known for its stability and great performance on a broad range of hardware: from Pentium Pro to modern CPUs.
Russia