I claim the ornamental design for a bag base plate footrest, as shown and described.
FIG. 1 is a front elevation view of a bag base plate footrest.
FIG. 2 is a rear elevation view thereof.
FIG. 3 is a top plan view thereof.
FIG. 4 is a bottom perspective view, taken from the left side. The bottom perspective view taken from the right side is a mirror image thereof.
FIG. 5 is a right side elevation view thereof; and,
FIG. 6 is a left side elevation view thereof.
The bag that is shown in broken lines illustrates the environment. The broken lines that connect the solid contour lines in FIG. 2 illustrate the boundaries of the claim. None of the broken lines forms part of the claimed design.