The ornamental design for a sportsboardstand, as shown and described.
FIG. 1 is a perspective view of a sports board stand showing my new design;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a top view thereof;
FIG. 5 is a bottom view thereof;
FIG. 6 is a left side view thereof;
FIG. 7 is a right side view thereof; and,
FIG. 8 is a perspective view of the sports board stand in use holding a sports board shown in broken lines.
The broken lines are for illustrating environment and form no part of the claimed design. The sports board stand is fabricated of transparent material.