What do you want to do? Increase the rate naturally, or with hormone drugs? Cytomel (T3), Synthroid (T4), Armour Thyroid (Desicatted thyroid gland) and Triancana, (which was a thyroid pro-homone and no longer available), are the choices.
For natural stimulation of the thyroid, read my post "The only SANE way to lose fat."