The ornamental design for a storagerack for headphones, as shown and described.
FIG. 1 is a left, rear perspective view of the storage rack for headphones according to the design, the right, rear perspective view being mirror symmetrical;
FIG. 2 is a rear view thereof;
FIG. 3 is a front view thereof;
FIG. 4 is a left side view thereof, the right side view being mirror symmetrical;
FIG. 5 is a top view thereof;
FIG. 6 is a bottom view thereof;
FIG. 7 is a left, rear perspective view thereof showing a possible environment, the right, rear perspective view being mirror symmetrical; and,
FIG. 8 is a right, front perspective view thereof showing a possible environment, the left, front perspective view being mirror symmetrical.
The broken lines are for illustrative purposes only and form no part of the claimed design.