There is a single flag matching these criteria: Flag of Dominica.
Black in Flags
Black in flags often conveys strength, determination, and resilience. It can also symbolize mourning, remembrance, or the struggle of a people. In some African nations, black represents the heritage and identity of the people. Historically, black has also been associated with resistance or defiance. Flags like those of Kenya, Angola, and Estonia use black as a bold statement of endurance and pride.
Purple in Flags
Purple is rare in flags due to the historical cost of purple dye, but where it appears, it symbolizes royalty, wealth, and spirituality. The color’s association with nobility made it prestigious, though few countries use it today. Modern examples include the flag of Dominica and the flag of Nicaragua, which both feature purple elements. Because of its rarity, purple stands out as a symbol of uniqueness and distinction.