Grille of Ventilation Fan

FIG. 1 is a perspective view according to a first embodiment of a grille of ventilation fan showing our new design; FIG. 2 is a front elevational view thereof; FIG. 3 is a rear elevational view thereof; FIG. 4 is a left side elevational view thereof; FIG. 5 is a right side elevational view thereof; FIG. 6 is a top plan view thereof; FIG. 7 is a bottom plan view thereof; FIG. 8 is a perspective view according to a second embodiment of a grille of ventilation fan; FIG. 9 is a front elevational view thereof; FIG. 10 is a rear elevational view thereof; FIG. 11 is a left side elevational view thereof; FIG. 12 is a right side elevational view thereof; FIG. 13 is a top plan view thereof; and, FIG. 14 is a bottom plan view thereof. The broken lines shown in the figures are for the purpose of illustrating portions of the grille of ventilation fan and form no part of the claimed design.