Timer - Useful for following those minute by minute instructions.
Skewers - Wooden or metal skewers are essential for kabobs. Some prefer flattened skewers, which tend to inhibit the partially cooked food rolling as you turn and make it possible to cook all sides of the food.
Disposable Drip Pans - These are placed under food cooked using the indirect method. A drip pan catches drippings from fatty foods, preventing flare ups. It can also be filled with water, wine, or marinade to flavor the food and provide wet heat.
Long Handled Tongs and Spatulas - Used for turning foods on the grill, the long handles allow you to work from a distance.
Oven Mitts - Heat resistant mitts prevent burns from working with a hot grill.
Basting Brushes - Frequent basting is key to all forms of barbeque. Brushes are also useful for oiling the grate prior to placing the food on the grill.
Meat Thermometer - Not strictly necessary for grilling thin cuts of meat or vegetables, a good thermometer is essential for determining the doneness of thick roasts.
Fire Chimney - Especially useful if grilling over a long period, when the fire will need refreshing regularly.
Grill Baskets - These are wire baskets with long handles. A basket shaped like a fish makes turning whole fish quick and easy. Grill baskets are also used to hold small items, preventing them from falling into fire.
Wire Brush - Look for one with a metal grill scraper on the front edge. This will make gleaning the grate a matter of minutes.
Whisk Broom - Handy for cleaning away ash from charcoal grills.
Squirt Gun - For a little Wild West action, put out those pesky flare ups with one of these. Also handy for anyone caught poaching off the grill.