Naturals for the hair ~

Basil brings luster to hair.
Rosemary enhances & brightens brunettes color.
Chamomile for blondes or light colored hair; bring golden highlights to brown hair; mixed with neutral henna, it adds highlights to very dark hair.
Others:
Bay, Comfrey leaf & root, Elderflowers, Horsetail (no, not an actual horse's tail), Lavender, Lemon, Mint, Myrrh, Nettle, Primrose, Raspberry, Rose, Sage, Willow, Yarrow.