The ornamental design for a stackablemonitorstand, as shown and described.
FIG. 1 is a perspective view of a stackable monitor stand showing my new design;
FIG. 2 is a front elevation view thereof;
FIG. 3 is a rear elevation view thereof;
FIG. 4 is a left side elevation view thereof;
FIG. 5 is a right side elevation view thereof;
FIG. 6 is a top plan view thereof;
FIG. 7 is a bottom plan view thereof;
FIG. 8 is a perspective view thereof, shown in an environment of use; and,
FIG. 9 is a perspective view thereof, shown in another environment of use.
The broken lines shown in FIGS. 8 and 9 illustrating another stackable display mount and on a monitor are environment that form no part of the claimed design. The remaining broken lines in the drawings illustrate portions of the stackable display mount that form no part of the claimed design.