The ornamental design for a modular lampshadeholder, as shown and described.
FIG. 1 is a top, front, and left side perspective view of a first embodiment of a modular lamp shade holder showing my new design;
FIG. 2 is a top, rear, and left side perspective view of a second embodiment of a modular lamp shade holder, the only difference from the first embodiment residing in the presence of a recess in the horizontal member which would permit the vertical member to be retracted;
FIG. 3 is a top plan view of the first embodiment thereof;
FIG. 4 is a front elevational view of the first embodiment thereof;
FIG. 5 is a rear elevational view of the first embodiment thereof;
FIG. 6 is a bottom plan view of the first embodiment thereof;
FIG. 7 is a left side elevational view of the first embodiment thereof; and,
FIG. 8 is an additional top, front, and left side perspective view of the first embodiment thereof, with the broken-line disclosure of a fragment of a pegboard and lamp shade being for illustrative purposes only and forming no part of the claimed design.