Are there cards more powerful than these?

O.k. so my friend owns the special shonen jump playable edition of obelisk, blue eyes white dragon, blue eyes malefic dragon (2 of them), mega morph, all the tyranno cards, well every good card you can think of. So without copying him what cards can i use against him? you can also recommend a deck or pack for me or just tell mandatory cards I should definitely use. thanks in advance.