For example for MTP: https://wiki.archlinux.org/index.php/Media_Transfer_Protocol The one that worked most stable for me was simple-mtpfs, but it's AUR.
It happens with other archwiki topics too, I encounter it regularly though can't think of good examples from the top of my head currently. E.g. the btrfs article mentions several AUR utilities though admittedly nothing important I need right now :)
And then some important development tools, like closure-compiler https://aur.archlinux.org/packages/closure-compiler/