Gambling
From FOnline: Aftertimes
The gambling skill is capped at 150 and has influence on how good the character is in all kind of games. At the moment, the gambling skill has no real use in-game.
Do not expect these items to have any effect yet, but Dice and Deck of Cards are obviously related to gambling.
Note: Maximum Gambling skill is 150. You can attempt to make it higher but it will go back to 150 and give you your points back.