Flat-bottom or "stand-and-stuff" shells have a flat base so they stand upright on their own and are intended to be filled after heating.
Specialty options include spinach and herb tortillas, nacho cheese–coated shells, and grain-free shells made with ingredients such as cassava, pumpkin, and avocado oil.
Some listings highlight a low-calorie profile; one tortilla specifically lists 60 calories per tortilla. (Not all items provide calorie details.)