Some of my favorites...
Stand in the light when you want to speak out - Crow
Life is both giving and receiving - Mohawk (some cherrytap people need to read that one)
Stolen food never satisfies hunger - Omaha
Ask questions from your heart and you will be answered from the heart - Omaha
It takes a whole village to raise a child - Omaha
We will be known forever by the tracks we leave - Dakota
Never sit while seniors stand - Cree
Each person is his own judge - Pima