Small utility heaters
You don't need a 1:1 iso transformer. Just get a doorbell transformer and pick a resistor to suit your needs. Although you can get better prices for lower-power transformers if you go to a distributor such as digikey.com and search.

Going to a lower voltage (say, 24 volts or less) will also be safer, since even if it's isolated, 120 VAC is perfectly capable of killing you if you mess up.