Congrats on the successful install! Arch is pretty tricky to get working (especially the first time) but it's totally worth it! Anyway, here are some package recommendations, idk how many of these you already know about but here are some that were useful for me!

• firewalld (block incoming connections, arch has no firewall by default)
• kde plasma (super flexible and powerful yet lightweight DE)
• foot (good and fast terminal for Wayland)
• st (good and minimal terminal for X11, also good entry point for suckless utils)
• fish (helps you get used to the cli, and you can make beautiful run prompts with starship)
• bottles (helpful for game launchers like Ubisoft connect)
• flatpak steam and other packages with 32 bit dependencies (sandbox 32 bit packages)
• protonup-rs (not sure if it works for flatpak stuff but it's a nice to have CLI program to simplify the installation of ge-proton builds)
• heroic launcher (so you don't have to install epic through lutris/bottles etc)
• QEMU with GPU passthrough (for those pesky games that won't work with proton, good to have and super easy to set up)

I'm also not a pro by any means, and please google these before installing them to make sure they are actually useful for your usecase. More advanced users: please do correct me if something is wrong or a bad idea because I started off not that long ago and I would love to learn more!

edit: fixed grammar and stuff

edit 2: I kinda assumed you had this but I forgot to mention, don't forget an aur helper like paru so you can install stuff easily from the aur!