the sculptural panel

“it can be wall mounted, wall leaning or free-standing...”

sculpture (noun):
the art of carving, modeling, welding, or otherwise producing figurative or abstract works of art in three dimensions, as in relief, intaglio, or in the round.

panel (noun):
a distinct portion, section, or division of a wall, wainscot, ceiling, door, shutter, fence, etc., especially of any surface sunk below or raised above the general level or enclosed by a frame or border.