Technically, you can cook any vegetable in the air fryer, but some don’t have the best results. For instance, air fryer broccoli and leafy greens are typically better when cooked in the oven or on the stove because the hot air of the air fryer often dries them out, resulting in more of a charred vegetable than fried or steamed. So this is subjective; if you love that charred result, you may think there aren't any veggies you cannot cook in the air fryer.