The ornamental design for tool display holder, as shown and described.
FIG. 1 is a perspective view embodying the utilization of tool display holder in which the broken line is for illustrative purposes only and forms no part of the claimed design;
FIG. 2 is a front view embodying the utilization of tool display holder in which the broken line is for illustrative purposes only and forms no part of the claimed design; the opposite side being a mirror image of the shown;
FIG. 3 is a left view embodying the utilization of tool display holder in which the broken line is for illustrative purposes only and forms no part of the claimed design;
FIG. 4 is a right view embodying the utilization of tool display holder in which the broken line is for illustrative purposes only and forms no part of the claimed design;
FIG. 5 is a top view embodying the utilization of tool display holder in which the broken line is for illustrative purposes only and forms no part of the claimed design;
FIG. 6 is a bottom view embodying the utilization of tool display holder in which the broken line is for illustrative purposes only and forms no part of the claimed design; and,
FIG. 7 is the perspective view embodying the utilization of tool display holder in which the broken line is for illustrative purposes only and forms no part of the claimed design.