The ornamental design for a desk accessory, as shown and described.
FIG. 1 is a perspective view of desk accessory showing my new design, the
environmental structure shown in dotted lines being for illustrative
purposes only;
FIG. 2 is a top plan view thereof;
FIG. 3 is a front elevational view thereof;
FIG. 4 is a side elevational view thereof taken from the left-hand side of
FIG. 3; and