I take a B complex with C and vitamin D3. A good multivitamin is a good idea, too. Make sure to take them at least four hours after taking your thyroid med, though, or you might have difficulty in absorbing the thyroid med.
I like a well balanced multivitamin with antioxidents, *lots* of B vitamins, digestants, enzymes and lipotropic factors. If you want to message me offline I'll be glad to tell you the brand name.