This was the flag of the Benin Empire, that was situated in modern Nigeria.
Flag of New Foundland & Labrador
Swaziland
Antwerp (Belgium)
Mozambique
Kyrgyzstan
Northern Marianas Islands
Central African Republic
Lombardy (Italy)
Libya
Libya's flag, consists of a simple green field with no other characteristics. It is the only national flag in the world with just one color and no design.