The ornamental design for a towablelitterrake, as shown and described.
FIG. 1 is a perspective view of the invention;
FIG. 2 is a top view of the invention; and,
FIG. 3 is a side view of the invention.
The wheels of the towable litter rake that are shown in broken lines in the drawings are for illustrative purposes only and do not form part of the claimed design.