PureDarwin is described as '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' and is an app in the OS & Utilities category. There are more than 100 alternatives to PureDarwin for a variety of platforms, including Linux, Self-Hosted solutions, BSD, Windows and Mac. The best alternative is Debian, which is both free and Open Source. Other great apps like PureDarwin are Linux Mint (Free, Open Source), Manjaro Linux (Free, Open Source), Arch Linux (Free, Open Source) and Fedora (Free, Open Source).
MerOS is a user friendly, good looking, general purpose Nix based GNU/Linux distro. It is ideal for those who want the most out of their computers, a well-designed desktop environment and an uncommon Linux experience.
The CLIP OS project is an open source project maintained by the ANSSI (National Cybersecurity Agency of France) that aims to build a secure, multi-level operating system, based on the Linux kernel and a lot of free and open source software.
CrunchBang++ is an open source and completely free [of cost (#!++ does include several of Debian’s non-free packages as well as the non-free repository)] computer operating system, designed as a continuation of the .