FIG. 1 shows a perspective view of a first embodiment for a design for a portable electronic device case.

FIG. 2 shows a front view of the first embodiment.

FIG. 3 shows a back view of the first embodiment.

FIG. 4 shows a left side view of the first embodiment.

FIG. 5 shows a right side view of the first embodiment.

FIG. 6 shows a top side view of the first embodiment.

FIG. 7 shows a bottom side view of the first embodiment.

FIG. 8 shows a perspective view of a second embodiment for a design for a portable electronic device case.

FIG. 9 shows a front view of the second embodiment.

FIG. 10 shows a back view of the second embodiment.

FIG. 11 shows a left side view of the second embodiment.

FIG. 12 shows a right side view of the second embodiment.

FIG. 13 shows a top side view of the second embodiment.

FIG. 14 shows a bottom side view of the second embodiment.

FIG. 15 shows a perspective view of a third embodiment for a design for a portable electronic device case.

FIG. 16 shows a front view of the third embodiment.

FIG. 17 shows a back view of the third embodiment.

FIG. 18 shows a left side view of the third embodiment.

FIG. 19 shows a right side view of the third embodiment.

FIG. 20 shows a top side view of the third embodiment.

FIG. 21 shows a bottom side view of the third embodiment.

FIG. 22 shows a perspective view of a fourth embodiment for a design for a portable electronic device case.

FIG. 23 shows a front view of the fourth embodiment.

FIG. 24 shows a back view of the fourth embodiment.

FIG. 25 shows a left side view of the fourth embodiment.

FIG. 26 shows a right side view of the fourth embodiment.

FIG. 27 shows a top side view of the fourth embodiment; and,

FIG. 28 shows a bottom side view of the fourth embodiment.

The broken-line features in the figures are for illustrative purposes only and form no part of the claimed design.