Ooni Pro comes with a wood and charcoal burner as a standard. You can use any charcoal that is suitable for cooking, as well as pieces of dry hardwood (up to 25cm (10") long and 4cm (1.5") in diameter) in this burner.
We have an awesome Pellet Burner accessory which is available on our website. We recommend Ooni Pellets, which are 100% hardwood and food-safe. The Gas Burner for Ooni Pro accessory runs on propane.