Some popular toppings for keto-friendly pizzas include low-carb vegetables like spinach, mushrooms, and bell peppers. Keto-friendly meats such as pepperoni, bacon, and sausage are also commonly used. Additionally, various cheeses, such as mozzarella, cheddar, or feta, can be added for extra flavor. Don't forget to season with herbs and spices like fresh basil, garlic powder, or red pepper flakes.