A lot of games with a console have it. Even different OS versions have it (Linux, Windows) You start typing a command, you press tab, and it shows you all list of things that start with what you typed.
I would do it for commands, like /s + Tab shows /say, /squad.
Also for /wiki. i.e. /wiki Iro + Tab would show a list of items that match, like all the Iron Ores, gear, etc.
Given that you already have a DB of all the items names on your Developer API, it shouldn’t be that hard to implement.