Joe, Portalmage of the Six

The legend rule allows players to have six of each legendary creature on the battlefield at once.
You can have six of each kind of card in your
deck other than Joe, Portalmage of the Six.
{6}: Create a copy of target creature. That
creature's control loses the game if there are six
or more creatures on the battlefield with that
name.
Each player's maximum hand size is six.