“What foods are good for your thyroid?”

I can't think of a thing. If there were any such nutritional therapy (as there is for diabetes, arterial disease, gluten-sensitive enteropathy, inflammatory bowel disease and pancreatic insufficiency and a host of other diseases), the doctor who diagnosed your thyroid problem would surely have mentioned it. If the course of therapy he or she recommends is somehow unacceptable, you can ask about alternatives.

Thyroid disease is usually an autoimmune phenomena & is not affected by diet. It is a hereditary problem. I don't know of any food that will affect the thyroid gland.