[tomkarho]

Let's break it down to traditional skill level terminology

Apprentice: Ubuntu, Fedora

Journeyman: Arch, Debian, Gentoo

Master: Linux From Scratch

[herewulf]

Master of the Universe: Guix System

Write your entire system definition once and never again.

[hulitu]

You forgot Slackware.

[jasomill]

Grandmaster: Ubuntu, Fedora