I claim the ornamental design for a guest slipper set, as shown and described.
FIG. 1 is a Perspective view of a guest slipper set showing my new design;
FIG. 2 is a Front view thereof;
FIG. 3 is a Back view thereof;
FIG. 4 is a Right-side view thereof;
FIG. 5 is a Left-side view thereof;
FIG. 6 is a Top view thereof;
FIG. 7 is a Bottom view thereof; and,
FIG. 8 is a perspective view of a guest slipper set showing in open position.
The broken lines in the drawings depict portions of the guest slipper set that form no part of the claimed design. The other broken lines are only for stitching on the guest slipper set.