Last month a new commit in the Official Arch Wiki has been made. It included a complete guide to Package Management systems found in all of popular Linux Distributions.
If you want to increase your knowledge of Linux Package Managers across more than one distribution, do follow this guide
Also this includes a guide to port "pacman" (the holy grail of package managers) to any Linux based distribution.
Also, RHEL is slowly moving it's base package management system from "yum" to "dnf" on RHEL systems and CentOS, and on Fedora users are being shifted towards using "rpm" instead of "dnf"/"yum"