FIG. 1 is an isometric view from the front, top and one side of a modular display rack showing my new design;

FIG. 2 is a side elevational view thereof from one side, the opposite side being a mirror image;

FIG. 3 is a bottom plan view thereof;

FIG. 4 is a front elevational view thereof;

FIG. 5 is a top plan view thereof; and,

FIG. 6 is a back elevational view thereof.

The structure shown broken lines in FIGS. 1, 2, 4, and 6 is for illustrative purposes only and forms no part of the claimed design.