The ornamental design for a toygrenade, as shown and described.
FIG. 1 is a front view of a toy grenade showing my new design;
FIG. 2 is a rear view thereof;
FIG. 3 is a left side view thereof;
FIG. 4 is a right side view thereof;
FIG. 5 is a top plan view thereof; and,
FIG. 6 is a bottom plan view thereof.
The dashed or broken lines shown in the drawings depict portions of the toy grenade in which the design is embodied that form no part of the claimed design.