The ornamental design for set of playing cards, as shown and described.
The file of this patent contains at least one drawing/photograph executed in color. Copies of this patent with color drawing(s)/photograph(s) will be provided by the Office upon request and payment of the necessary fee.
1.0 is a front view of a first suit of the set of playing cards.
2.0 is a front view of a second suit of the set of playing cards.
3.0 is a front view of a third suit of the set of playing cards.
4.0 is a front view of a fourth suit of the set of playing cards.