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You might want to add a tuning coil to that list.

If you live close to an AM radio station, you just need a hunk of metal and a diode... it doesn't need to be resonant or tuned in any way.

Urban legend has it that you can even hear them via metal fillings in your teeth.

Of course. But if you have one strong station close to you, it will overwhelm any other signal and you'll hear it.