The ornamental design for a virtual rangefinder, as shown and described.
FIG. 1 is a top plan front view of a virtual range finder in accordance with the present invention for use in a simulated video game tank battle, showing its tab positioned to display simulated ranges to a specified tank (vehicle) target based on metrics provided for gaming purposes;
FIG. 2 is a back view thereof;
FIG. 3 is a top view thereof;
FIG. 4 is a bottom view thereof; and,
FIG. 5 is a right side elevational view thereof; the undisclosed left side elevational view being a mirror image thereof.