Sometimes, don't you have a time that you are looking for foods with some particular nutrients in mind, like foods rich or low in minerals, vitamins, proteins, or such? In my case, I often look for foods rich in magnesium!
Here is the Nutrients in Food Tool that you can find foods by highest or lowest in certain nutrients, calories, and etc, which I think is very useful. To start out with, try it out with 'magnesium' as nutrients. Do you know what comes in the 1st place? Check it out!