The ornamental design for a samplerack, as shown and described.
FIG. 1 is a front isometric view of a first embodiment of a sample rack showing my new design;
FIG. 2 is a rear isometric view thereof;
FIG. 3 is a front elevational view thereof;
FIG. 4 is a rear elevational view thereof;
FIG. 5 is a top plan view thereof; and,
FIG. 6 is a right side elevational view thereof; and
Left side elevational view is a mirror image of FIG. 6.
The portions of the sample rack depicted in broken dash lines represent the bounds of the claim and form no part of the claimed design. Neither the lines themselves, nor the region within said lines, form any part of the claimed design.