Arch Linux

Gotta agree with Ozymandias aliases are the way to go.

I've set up a few different aliases "search" which is just pacman -Ss "install" (pacman -Sy) "update" (pacman -Syyu) "remove" (pacman -Rns) and finally as to your question about unneeded dependencies I've got "clean" which first does an orphan check/clean (pacman -Qtdq | pacman -Rns -) and afterwards also cleans the package cache (pacman -Sc) Also the aliases are automatically prefixed with sudo (if it is installed).

This way I simply run update and afterwards clean and my system is up to date and cleaned of orphans.

I've created these aliases back when I was still using 3Distros (Arch,Debian/*buntu, Fedora) so my alias definition comes after a little script that determines the correct package manager and, depending on that, sets the aliases. But that's of course only necessary if you use different distros and want your aliases to be portable.

Tl;dr: Set up aliases for things you wanna do often. Check the wiki for reference if you only want to do something every so often.

I read the man page and used --help more than I could remember, now the stuff I use stuck with me. Base pacman commands are actually named and shortened pretty intuitively. I only use AUR helpers for exactly that, so I pretty much don't use all the extra functionality.

curl cheat.sh/pacman'

If you install paru then all you need to do is type paru to start a full system upgrade, its an alias for paru -Syu.

I'd just like to point out the objective fact that Yay is the best-named AUR helper ^.^ :3

As for the actual question, I'm not sure how many I should be using? I kinda just remember -Syu and -Ss and -Ql because I use them muchly; for most else pacman --help -Q/S/whatever helps lots. For the last little bit, there's rage-searxing and doing what some mean person on the Arch forums says to do :D

Edit: I think a mean person from the Arch forums downvoted me :D

I don't use yay so can't help you there. For me the most useful pacman commands just got memorized after doing an install. I don't think you need to memorize that much.

But to your question, instead of mnemonics you could use aliases instead for bash or zsh. that way you can use your own made up commands (or even mnemonics)