Mostly are server sided commands.
/finduser probably returns some kind of info about the specified player
/worldstatus might will return some kind of server statistics in real time
/appeal no idea
/invincible doesn't need explanation. Makes your HP never goes down.
/instance probably for start an instance by hand for test purporses
/blocklogout blocks the log out permissions to an specific player, this means he can't logout of the game until it gets unblocked or forcekills the client
/allowlogout disables the last command action
/realname returns the name which the user is registred on the server?
/liename returns the ID?
/cm chat commands? I'm not sure it returns this error: