Abstract: CLAIM The ornamental design for holder for game tiles, as shown and described. DESCRIPTION FIG. 1 is a perspective view of a holder for game tiles, showing our new design, the design in an assembled position; FIG. 2 is a front elevational view of one of the end pieces shown broken away for clarity, the rear being identical; FIG. 3 is a right side elevational view of FIG. 2, the left side being identical; FIG. 4 is a bottom plan view of FIG. 2; FIG. 5 is a front elevational view of the intermediate front pieces, shown disassembled and without the end pieces for clarity; FIG. 6 is a left side elevational view of FIG. 5, the right side being a mirror image; FIG. 7 is a top plan view of FIG. 5, the bottom plan being a mirror image; FIG. 8 is a cross-sectional view of the lower half of the intermediate front pieces in FIG. 5; FIG. 9 is a front elevational view of the left side of one of the two pieces shown in FIG. 5, shown disassembled for clarity, the right side being a mirror image; FIG.