Here are some of the available commands.
You may use the @commands in-game to see the full list.
@security - To set a security password to enable item and character protection.
@checkreward - To see the list of rewards, what you've received, and what you'll receive the next day.
@joinchannel - To join the server's discussion, trading, and recruitment channels #main-en #market #recruit.
@monsterinfo - To see the monster's details, such as stats, experience, and drops.
@refresh - To sync your client with the server's current data; useful when some mobs or players are out of position.
@LGP - Enables playing with effects off with simplified skill effects on to reduce lag created by excessive skill spam.
@autotrade (PR) - To allow merchant classes to continue vending while offline.
@chatroom (PR) - To create a clone of yourself advertising something, which you can leave with an opened chat room.
@whobuy & whosell (PR) - To display a list of players who are currently buying or selling certain items, including their prices and quantity.
Commands with "(PR)" are for Premium Subscribers.