Aside from YUM, Apt, snaps, and Flatpak, there are a host of other package management systems. Pip and RubyGems are programming-language related methods of distributing packages to systems; there are more than these two, but they're by far the most popular right now.
Pip installs packages (Pip) is included by default in recent Python installations. Gem is just a play on the fact that it is for packaging Ruby elements; it, too, is included in recent Ruby installations.
We're going to touch on installing software using these package managers.
