The ornamental design for a holder for weightrack, as shown and described.
FIG. 1 is a top, front, right perspective view of a holder for weight rack showing my new design;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a left side view thereof;
FIG. 5 is a right side view thereof;
FIG. 6 is a top view thereof;
FIG. 7 is a bottom view thereof; and,
FIG. 8 is a top, front, right perspective view of a holder for weight rack showing my new design of FIGS. 1-7 in its exemplary environment.
The broken lines adjacent to the shaded region define the bounds of the claimed design and form no part thereof. The broken lines depicting the reminder of the holder for weight rack and the exemplary environment show features that form no part of the claimed design.