In Duelist Kingdom Joeys Deck was supposed to be bad; if he did not trade of some of the monsters for spells/Traps he had nothing else.
As it was portraied that he liked big beat sticks i looked for the biggest and baddest in the kategories warrior, beast warrior and beasts.
I also gave him the King/Queen/Jacknight because drawing the kingsnight and having the other peace on the field/getting it with unexpected die is kind of gambling.
I changed the Spell/Traps to unexpected die and heart of the underdog, because it interacts with the normal monster better and it give a reason, why he gives underdog to the child later, when he updates the Deck to contain less (normal) monster and it does not impact the deck as much.