If you don't have cannellini and black beans on hand to make this kale and bean soup, you can substitute different beans in a pinch. Cannellini beans are a white bean (and they're also known as white kidney beans). If you don't have them on hand, you can use another white bean like a great northern bean or navy beans. They will slightly change the taste of the soup, but not a lot. If you don't have black beans, you should run to the store to get them. There aren't really any black beans that are similar enough to keep the flavor of the soup. If you don't mind changing the flavor, red kidney beans would work as far as texture, but the taste is really mild compared to black beans. Red kidney beans would taste good in this soup though.