Magnesium is a significant deficiency for most. It controls over 300 functions in the body. I have seen it improve energy, calm the body, stop leg cramps, improve sleep, stop headaches, normalize the bowel when the dosage is correct, and stop muscle aches.
Omega 3 is a big deficiency for most. Flax oil and fish oil are two good sources. If you use fish oil, Be sure to get a high quality product that is distilled or purified. Cheaper oils likely have not been purified. With oils, you get what you pay for.