What is the best yu-gi-oh card ever?

There are many cards that are favored by many gamers across the world, and I really doubt there is a single overpowered card, so instead I'm going to provide a few cards, with the reasons given by other gamers.

NOTE: These reasons were provided by other gamers, not me. Make up your own mind.

[Black Luster Soldier: Envoy of Beginning] because it have the ability to attack two monster in one attack phase or destroy any monster on the field with its ability.

[wave-motion cannon] it is the best card ever because for every stanby phase, of the owner, that is in play it gets one spell counter, you can send it to the graveyard whenever you want and the opponents recieves 1000 LP for every spell counter