There are ten veggies with a lot of protein. Protein is an essential nutrient your body uses to repair and build tissues. Animal foods are usually the highest in protein. Some plants also contain decent amounts of it too. Watercress is one of these plants. Watercress grown in water and is very high in protein. One thing you should not do with this plant is boil it, because that will get rid of the antioxidant properties it has.