There are a few dog foods on the market that are similar to Pro Plan. Some of these include Royal Canin, Iams, and Hills Science Diet. All three of these brands offer a variety of formulas that are designed to meet the needs of different types of dogs. For example, Royal Canin offers a formula for small breeds, while Iams has a formula specifically for large breeds. Hill's Science Diet also has a line of grain-free dog foods.