I use:
spirulina (get it at a health food store- it's blue green algae)
turmeric
madder root
rosemary powder (makes tan- not green
rose kaolin clay
green clay
etc. etc. etc
I find lots of ideas by googling around on the net.
canned pumpkin for my pumpkin soap
rosemary for a light greeny gray
I LOVE LOVE LOVE parsley for green - I use this for my gardener's bar
coffee for brown/tan