I think all of the appliances that will work by the use of electricity needed a transformer. Other appliances has their own transformer.  However, there are also other appliances needs a transformers like a 120 Volts appliances. Here in Philippines, our household voltage is 220 Volts, so appliances that are 120 Volts needed a transformer so that it will fit and suit to the 220 Volts household voltage. If you plug a 120 Volts appliance without a transformer in a 220 Volts source, the appliance will be damage because of over-voltage supplied in it. 120 Volts appliances must be plug in a 120 volts source, 220 Volts appliances must be plug in a 220 volts source.