what are the rarest yugioh cards?
['Skuna, the Leonine Rakan.', 'Shonen Jump Championship Cyber Stein.', 'Armament of the Lethal Lords.', 'Iron Knight of Revolution.', 'Amatsu-Okami of the Divine Peaks.', 'Signed Japanese Tournament Blue Eyes Ultimate Dragon.', 'Tyler the Great Warrior.', 'Tournament Black Luster Soldier.']