Here's a strategy if your child has a very limited variety of food, a way to expand their diet and to expose them to more types of foods. You can start with their safe foods and slowly expand by chaining them to similar foods. For example, you could start with this twisty pretzel. We could try to do a straight pretzel the next time.
Or you can even combine them with preferred foods that they already like. So now I like peanut butter on my sandwich, let's try my pretzel in the peanut butter. We can start to expand that way.