I had experience with biofeedback as a child for controlling stress. 11 yr old kid in 1983 and I could control a computer with my mind. It was pretty cool for me. [make a sound go up and down, and controlling a basic video game block).
More similar to neurofeedback is TENS. I had a TENS machine about 18 years ago I got from eBay. It pulses making your muscles go back and forth against each other.
At a very low setting, it can help control migraines when put on the temple.
But the thing that makes neurofeedback better, is it has a better level of control than the TENS machines do and works at a lower frequency. TENS is more randomized.