Many kitchenware and grilling stores carry cooking planks in a variety of woods cedar, alder, maple, hickory, oak, mesquite and apple.

NPR: Where There's Smoke, There's Flavor

Also, Traeger makes eight flavors of wood pellets, just like the hardwood chunks I buy for my smoker, apple, cherry, mesquite, oak, etc.

FORBES: 5 Unique Grills To Fire Up Your Backyard This Summer