In addition to being calorically dense, eggs contain vitamin D which is hard to get from food.
Oats are a whole grain loaded with health benefits including improving gut bacteria due to containing the prebiotic beta-glucan, a soluble fiber.
Fish is a rich source of protein.
Avocados are especially rich in folate, potassium, and vitamins C and K.
Dried fruit contains more highly concentrated calories in a lower volume than fresh fruit.
Full-fat Greek-style strained yogurt is loaded with protein, probiotics and calcium, and it also contains Vitamin B12.