I'm an Electrical Engineer, so I get a Lot of questions on energy harvesting, usually referring to Tesla's work from a century ago. I refuse to list any of their advertisements, because I won't promote their Obfuscation; even if they are little white lies.
Most say you harvest either electromagnetic (EM) energy, electrostatic energy, or cosmic energy. Technically, you can collect energy from these sources, but the amount of power you are able to collect is minuscule! The only useful application of ambient energy I'm aware of, is a crystal radio.
The energy harvested if done carefully, is in the fractional wattage range. I have done this myself as a curiosity, and managed to light a single high efficiency red LED...with not very much light; for a lot of hardware!
This is what you should think of, when you see these advertisements:
This makes about as much power as these 'secret' power harvesting equipment designs!
The EM energy is most available, and is tapped by using an antenna. Most antennas are 50 ohms, and you will see about 0.01 volts on a good day. Using ohm's law (E=IR) we know that 0.01 volts, divided by 50 ohms equals 0.0002 amps. If we use P=IE to calculate power collected, we have 0.0002 amps times 0.01 volts equals 0.000002 watts! It is hard to charge a power system using 2 microwatts of power! If you built over a hundred thousand antennas, and rectifier / storage circuits, you could harvest one watt!
Static electricity is even worse, in spite of it's high voltage levels; the current is extremely low amperage! Power here would be even less, unless you could harness lightning; which is not possible to do safely.
Cosmic energy is most commonly referred to as radiation, and is a very low level also; with the added benefit of being a deadly poison.
Here is a good article on cosmic energy:
https://www.nuenergy.org/nikola-tesla-radiant-energy-system/
Interesting to note that the atmosphere protects us from radiation exposure from cosmic rays, by absorbing them! If there was any truth to this 'technology', NASA would be using it to power spacecraft!
Even if you include 'resonance' from the above article, we need to Factor in the fact that no circuit is 100% efficient. So a resonant circuit can't harvest more power than is applied to it!
So next time you see one of these ads, delete it and save yourself some time!