Herbs I have used in sachets

Marigold (protection/legal matters), horehound (protection/mental powers), mint (travel) and yarrow (courage).
Chamomile - calming.
Lavender, peppermint and allspice - calming and spicy. 
Peppermint - calming.
Cardamom, allspice and cloves - 'autumn'.
Pepper, ginger, cinnamon and cardamom - chai.
Star anise, mullein leaf and rosemary - nightmare repellent.
Lavender- peppermint and chamomile - soothing and calming.
Cinnamon (protection), Thyme (courage) and Bay (strength) - 'warrior' mix.
Mullein and rosemary - nightmare repellent.
Rose, cinnamon and lavender - by request
Aniseed - all heal.
Vervain (protection, ♀, Earth), Marjoram (wealth, ♂, Air), Juniper (health, ♂, Fire), Catnip (happiness, ♀, Water) - Merry meet, merry part and merry meet again.
Orange peel and cinnamon - energizing.
Rose petals, cardamom and peppermint - 'Lily's Mix' 
Fennel - protection 
Dill - calming
Cinnamon sticks, whole cloves and nutmeg - 'Autumn in Avacal'
Peppercorns, Cardamom, Nutmeg, Cloves, Cinnamon - 'Dana's Delicious Mix' 

Future Endeavours (prone to change)

~Norse herbs (referencing http://www.cs.vassar.edu/~capriest/vikfood.html)

~Anatomy of mulled beverages

~Herbs of the Crusades

Why Lavender Sachets?

     When I first started making sachets, mainly for largesse, I used lavender as it was easy to obtain and few were adverse to its scent.  Upon further research for other uses for lavender, I have stumbled upon some beneficial reasons to the sachets.
      Medieval and Renaissance women used to place lavender in the layers of cloth or lay freshly washed clothes on lavender to dry, thus infusing the fabric with the flowers scent.  This is attributed to why these women were called "lavenders".  The scent of lavender is a marvelous moth repellent and can also be used as a mosquito repellent. Canadian Tire is selling various lavender plants with a sign saying they will keep mosquitoes away.
      Lavender is also used to both lift and relax the spirit.  Whenever I make a sachet for a child or to ease nightmares I include lavender.  I find it relaxing and soothing, but the scent is very familiar so it can also lift my spirits.  According to Scott Cunningham "the plant is so powerful that if when depressed, one gazes upon the plant all sorrow will depart and a joyous feeling will settle upon the observer."  Hildegard of Bingen stated "It curbs very many evil thins and, because of it, malign spirits are terrified."  Not too shabby for a little purple flowered shrub.
     I gain more respect for this fragrant flower the more research I do and I happy that I can share it with others, even if they just think it smells good.

Sources:
The Lavender Garden: Beautiful Varieties to Grow and Gather by Robert Kourik 
The Completed English Translation of the Classic Work on Health and Healing translated by Priscilla Troop