Sage, thyme, lemon verbena and rosemary will all happily hop from garden to pot, smelling wonderful all the way. Fresh peppermint tea is amazingly refreshing stuff - if you make it as sun tea, you just can't get much closer to nature. And if you are pregnant, do not use pennyroyal. In addition to being refreshing, peppermint tea is good for headaches, and mixed with yarrow, it is good for colds. Sage tea makes an excellent gargle for sore throats and laryngitis.
Lavender is another one good for headaches, as well as for promoting natural sleep.
Basil can be used for stomach problems and to ease coughs. Lemon Balm tea will relieve cramps. Lemon Verbena tea is very sedative. Catnip tea is very soothing for children, and helpful for insomnia. Rosemary tea is scholar's favorite, as it aids in clear thinking and helps memory.