There are really endless options depending on the flavors you like to eat! I like to use a mixture of cauliflower, bell peppers, and onions. The peppers and onions remind you of fajitas and really hold onto those spices. You can also add roasted mushrooms or broccoli, sauteed zucchini and corn, roasted sweet potatoes, fresh cherry tomatoes, and so much more. It's fun to adapt the recipe based on what's in season, so get creative with it!