Beach Towels and Beach Toys, Umbrellas if you want them.  Also, when you make your trip to the grocery store, don’t forget to pick up extra paper towels, toiletries and toilet paper if you think you’ll use more than is provided.  Unless previous guests left them, you’ll also want to grab/bring laundry detergent and any spices, oils, vinegar, etc. that you need for your meal preparation.