I'll start with one that I just realized yesterday.

Just three grams (1 teaspoon) of cumin seeds provides eleven percent of your daily need for iron (all for just one carb). ELEVEN! And iron can be a challenge, especially if you don't eat much nuts, seeds or legumes (all great sources). Cheese is very low in iron, and one jumbo egg only gives you 6%, so don't think you're off the hook, vegetarians!

Three grams of cumin seeds also provides 3% of both calcium and magnesium, just as an added bonus.

Fry them in some oil before adding them to your beans, soup, curry etc.

Most grocery stores sell them, but they'll be expensive. Look at Indian stores, where you should be able to get 100 grams for under three bucks, maybe even under two.