US D568173 S1
The ornamental design for a napkin holder, as shown and described.
FIG. 1 is a front perspective view of a napkin holder showing my new design;
FIG. 2 is a front perspective view of FIG. 1 shown in an alternate position;
FIG. 3 is a front perspective view of FIG. 2 shown in condition of use;
FIG. 4 is a front view of FIG. 1 shown in an open position; and,
FIG. 5 is a rear view of FIG. 4.
The broken lines shown in the drawing disclosure are for illustrative purposes only and form no part of the claimed design.