This mod adds /op and /deop to single player worlds, which can be used if the world is Opened to LAN.
Only the host is required to install this mod.
If you wanted to open a creative world to LAN but are afraid of random people on the LAN joining and griefing, you can use this to only give select people special permissions to use commands. This mod is a feature included in one of my other mods, Ngrok LAN (Modrinth, Curseforge), to open your Single Player worlds as Servers. If you have Ngrok LAN installed you do not need this mod.
This mod is available under the MIT license.