Dryer. If you have a propane dryer, you should be able to easily convert it to natural gas. Keep in mind it needs to be vented properly to be safe and efficient.
Range. Home cooks and chefs love cooking on gas. Most new ranges are sold for natural gas, if you kept the original pieces, the conversion is as simple as reinstalling those pieces. A conversion kit can also be purchased. As a general rule of thumb, the more expensive the appliance, the more expensive it will be to convert.
Grill, gas fire place. These are other appliance you may consider plumbing for natural gas.