Must say, I was not aware / did not remember the cal one, which is pretty nice. The two that are possibly missing are man (for manual reference info pages) and rmdir (maybe because it sometimes happens folks remove the / root directory and everything else on the hard drive with one command).
Apt of course is for Debian/Ubuntu based package management systems, so Manjaro and Arch users would look at pacman instead, and YUM is used for RPM-based distros. But a newer approach is to use AppImage, Snaps or Flatpak files which install universally across all distros.
But these really are the essential ones to know about.
So you are planning to switch from Windows to Linux, or have just switched to Linux? Then, here are the 20 useful Linux commands for Newbies.