The ornamental design for a padholder, as shown and described.
FIG. 1 is a perspective view of the pad holder;
FIG. 2 is a front view of the pad holder;
FIG. 3 is a rear view of the pad holder;
FIG. 4 is a right side view of the pad holder;
FIG. 5 is a left side view of the pad holder;
FIG. 6 is a bottom view of the pad holder; and,
FIG. 7 is a top view of the pad holder.
The broken lines shown in the drawings illustrate portions of the pad holder and form no part of the claimed design. The broken away symbols in the drawings indicate the appearance of any portion of the article between the break lines forms no part of the claimed design.