|Cast iron floor registers and air returns can be found in all sorts of patterns and shapes, even round. They are durable, and resistant to scuffs caused by shoes and normal vacuuming. So if you're looking for heat registers that will fit most any decor, these would be a good type to consider. They're also historically accurate as replacement items, and are available in extra large sizes.
Do you use a runner to protect the carpet or hardwood on your stairs? If so, you should consider using decorative stair rods to hold them in place and add a personal touch to your stairwells. They come in many styles, finishes, and materials, so one is sure to fit your home. And be sure to check out the radiator flanges and decorative radiator keys for a new touch to an old fixture.