I claim the ornamental design for a license plate guard, as shown and described.
FIG. 1 is a perspective view of a license plate guard showing my new design;
FIG. 2 is a front elevation view thereof;
FIG. 3 is a back elevation thereof;
FIG. 4 is a left-side elevation view thereof;
FIG. 5 is a right-side elevation view thereof;
FIG. 6 is a top plan view thereof;
FIG. 7 is a bottom plan view thereof;
FIG. 8 is a perspective view thereof; and,
FIG. 9 is a cross-section view taken from cut line 9-9 in FIG. 2 showing the license plate guard.
The broken lines depicting part of a license plate in FIG. 8 illustrates the environment of the license plate guard which forms no part of the claimed design.