WebMD include animal products (salmon, eggs, yogurt etc.). But to recommend a particular food based on one key nutrient (salmon and omega-3; eggs and choline) is to mistake the part for the whole and to neglect subtle interactions that nutrients have on each other. Also, many recommend foods (animal products) are high in anti-nutrients (toxins such as pesticides, fertilizers, and heavy metals which animals store in their fat and milk - in addition to cholesterol and saturated fat which offer no benefit to the body), and these supervillians reduce or eliminate altogether the benefits derived from the vitamins and minerals animal foods do contain.
Let's go back to basics. (I know you've heard this already but it merits reiteration.) What is a superfood? In its purest definition, superfoods are those foods which contain the greatest amounts of nutrients per calorie. In other words, superfoods are the most nutritionally dense foods. As can be seen in the list below, created by the illustrious Joel Fuhrman, MD, who factored in hundreds of vitamins and minerals and other antioxidants and phytonutrients, leafy green vegetables are highest in nutrient density, followed by other vegetables, then fruits, then beans.
Grains, animal products like tuna and milk and eggs, as well as nuts not to mention refined carbs, oils, and other packaged, processed foods are all much further down the list. Making plant foods (greens, beans, sweets, seeds) the true superfoods. And the more of these you eat, the super-er you are.