This add-on pack includes the custom balls:

BLACK HOLE
CLASS OF 1812
CUE BALL WIZARD
GOIN' NUTS
HAUNTED HOUSE
TEED OFF
VICTORY

Once unlocked and selected, Custom Balls can be used on any table. To change your pinball to be a Custom Ball, select Extras from within the Options of any Table Menu.

More details on the official game page of Gottlieb Ball Pack 1 ...