We claim the ornamental design for a greeting card holder, as shown and described.
FIG. 1 illustrates a perspective view of a greeting card holder of the present invention;
FIG. 2 illustrates a front view of the greeting card holder of the present invention;
FIG. 3 illustrates a top view of the greeting card holder of the present invention;
FIG. 4 illustrates a right side view of the greeting card holder of the present invention, the left side view thereof being the same as the right side view;
FIG. 5 illustrates a back view of the greeting card holder of the present invention; and,
FIG. 6 illustrates a bottom view of the greeting card holder of the present invention.
The broken lines of FIGS. 1–6 are for illustrative purposes only and form no part of the claimed design.