chamomile is for nervous issues, heartburn,and is very supportive of the female cycle.
peppermint is good for stomach but avoid in third trimester as it may increase braxton-hicks contractions.
horsetail is high in silica, for hair, skin and nails
dandelion is good for the liver and helps with odema
ginger and lemon is a great pick-me-up when you just *need* a coffee


avoid strong teas such as
rosemary (may elevate blood pressure)
lavender (may decrease blood pressure)
and
red raspberry in early pg as it ripens the cervix for delivery

there's a whole heap more info in "eat right for your baby" by peter j d'adamo, ISBN 0-425-19614-3, we used his books in nutrition class and i've used the type "O" diet for years to control PCOS.