If you've ever played on a server you probably used the commands like /spectator /creative and /survival instead of /gamemode survival. That's because they are easier to type and remember. This fabric mod aims to add these commands in mod form instead of as a plugin. Now you are able to use the commands you would usually use on a server in singleplayer. The mod should work in most recent versions if not try 1.16.5. I hope you enjoy!