Not knowing what diets you have used, or what your current diet restrictions are, its impossible to suggest a specific food. It also sounds like you are interested in self observation of results. Knowing this, you might find an excel chart I'm working on to be helpful (StapleFoodsNutrition.xlsx).
It's a work in progress, but the goal is to find a basic grouping of staple foods that check off all micro-nutritional DV's. This is useful for me so I can keep track of the foods I incorporate to my diet, check off the nutritional values I have met, observe any changes, and finally move to the next value of interest. Basically, I add a food to the list, test it the next week, adjust my serving size, observe and repeat. Sadly, you'll have to do the work to understand the file, and incorporate new foods, but its a starting point.
So far I've learned a decent amount about each vitamin and mineral on a much broader scale, and the difficulties of incorporating each without the use of supplements. My end goal is to ease a skin condition of mine. So far results wise, I have found that I wake up consistently at an earlier time without alarms, and my extremities feel warmer (Raynaud's-like symptoms).