Yes, there are a few fruits that you can find beginning with the letter U and many of them are available to buy or even grow in your location. For instance, popular begins with this letter are the Ugli fruit, a hybrid citrus fruit that has both sweet and tangy taste, the Umbu, a tropical Brazilian fruit, the Uvaia, an aromatic fruit from South America, and the Usuma, in Africa. The Ugni, also know as the Chilean guava, can be cultivated if you have the right climate and the garden. Some are not very common in the supermarkets, but specialist stores or online nurseries should stock them.