Molded articles are provided. An exemplary molded article includes an inner panel portion, a main body portion, and a contoured portion extending between and interconnecting the inner panel portion and the main body portion so as to surround the inner panel portion and be surrounded by the main body portion. The contoured portion includes contoured corner segments and contoured intermediate segments extending between respective pairs of the contoured corner segments. The contoured intermediate segments have a first maximum thickness. The contoured corner segments have a second maximum thickness. The first maximum thickness of the contoured intermediate segments is greater than the second maximum thickness of the contoured corner segments. Related methods, assemblies, and apparatus are also provided.