The ornamental design for a grinder accessory, as shown and described.
FIG. 1 is a isometric view of the grinder accessory, which embodies my design;
FIG. 2 is a isometric view of the grinder accessory;
FIG. 3 is a bottom plan view of the grinder accessory;
FIG. 4 is a top plan view of the grinder accessory;
FIG. 5 is a front side view of the grinder accessory;
FIG. 6 is a back side view of the grinder accessory;
FIG. 7 is a left side view of the grinder accessory;
FIG. 8 is a right side view of the grinder accessory; and,
FIG. 9 is an exploded view of the grinder accessory, shown in use.
The grinder components exploded depicted by broken lines in FIG. 9 has been shown for the purpose of illustrating an environmental feature that forms no part of the claimed design.