The ornamental design for a plate with a tread pattern, as shown and described.
FIG. 1 is a perspective view of a plate with a tread pattern showing our new design; and,
FIG. 2 is a front view thereof.
The dot-dash-dot broken line perimeter surrounding the plate with tread pattern depicts the boundaries of the claimed design and forms no part of the claimed design. The evenly-spaced broken lines depict portions of the plate with tread pattern that form no part of the claimed design.