FIG. 1 is a perspective view of our new scaffold wrench holster with retractor showing our new design; FIG. 2 is a front elevational view thereof; FIG. 3 is a rear elevational view thereof; FIG. 4 is a right side elevational view thereof, the left side being a mirror image thereof; FIG. 5 is a top plan view thereof; and, FIG. 6 is a bottom plan view thereof. The scaffold wrench depicts environmental structure that forms no part of the claimed design.