What are foods that contain lots of protein?

Here's a link : Meat, poultry, fish, cheese, seeds are some examples. Read this: https://www.nlm.nih.gov/medlineplus/ency/article/002467.htm

Protein sources.: Fish, egg whites, chicken, turkey, pork and milk are good, lean sources of healthy protein. Choose skim or 1% milk to keep it leaner. Red meat is a good source, technically, but also contains a lot of unhealthy fat so should be limited. And prepare your protein in a healthy way - grill, bake, broil. Don't fry or sauté.