THREE DIFFERENT COLOR TYPES HAVE FLAG GROUPS
You may think that each flag is unique to its country, and usually it is, but there are some consistent patterns and colors that we can see in linked countries. Islamic countries often use the star and crescent moon to represent their religious beliefs, but there are many more such connections around the world. There are 3 main categories used to group countries that use the same colors in their flags.
These are the country flags in Eastern Europe where red, white and blue colors are used. They were once united by the Soviet Union, but have created their own flag using the same colors since they gained independence. Countries in this category: Croatia, Czechia, Russia, Serbia, Slovakia and Slovenia..
Country flags in this category use only red, yellow and green and are all of African origin. Countries in this category are: Benin, Cameroon, Republic of Congo, Ethiopia, Ghana, Guinea, Guyana, Mali, Mozambique, Senegal, Togo, Zambia and Zimbabwe.
This category consists of flags in which only white, red, green and black are used in their flags. Typically these countries are centered in the Middle East and they are: Iraq, Jordan, Kuwait, Sudan, Syria, United Arab Emirates and Western Sahara.