Slackware Linux
The secure and simple Slackware distribution is definitely a Unix Linux distribution, it is optimal for working with servers. An ancient and peculiar Linux distribution — that's how you can characterize it, a technology like Systemd is alien to its developers.
The stable version of Slackware 14.2 has been released. after many beta versions, it comes with a 4.4 kernel. Two kernel options are available - monolithic and modular builds, support for such graphical shells KDE 4.14.21 (KDE 4.14.3 c kdelibs—4.14.21), Xfce 4.12.1. The distribution will make you work on configuring it, a lot of things will need to be done manually.