Also: cinnamon and peppercorns. And, heating the spices in the milk (perhaps an even mix of whole milk and water) infuses the flavors better. (Half-and-half or heavy cream, if you're making chai ice cream. :) )

Star anise and licorice root also make good herbal teas.

Or a few mint leaves for a soothing flavor...

Try a pinch of lavender for a refreshing variation.