I claim the ornamental design for a jack-stand tray, as shown and described.
FIG. 1 shows a jack-stand tray engaged with a conventional jack-stand, the dashed lines indicate environmental subject matter only which forms no part of the claimed invention;
FIG. 2 shows a front perspective view of the jack-stand tray showing a top, front, and left side thereof;
FIG. 3 shows a rear perspective view of the jack-stand tray showing a top, rear, and right side thereof; and,
FIG. 4 shows a bottom view of the jack-stand tray.