I have hashimoto's and grave's disease. i heard to stay away from soy and soy products because it is goitrogenous food. is this true? are there more?

Unknown: The main issue is staying away from foods that might have an elevated iodine concentration. That is more important. Maybe you should schedule an appointment with a dietitian to get a handle on safer foods.

Soy: Soy indeed can inhibit iodine metabolic pathways in the thyroid, and make hypothyroid conditions worse; other goitrogenic foods are: Broccoli, Cauliflower, Kale, Brussels Sprouts, Mustard Greens, Radishes, Spinach, Strawberries, Peaches, Soy-Based Foods, Peanuts. These are not absolutely forbidden; it is frequency and quantity that matters; if you are monitored, then you will be ok; be moderate;