This flag on FOTW website
Cape Verde
Castile and León
Castile-La Mancha
Cayman Islands
Central African Republic
Chicago
Chile
China - Naval Ensign
China Republic (1912-1929)
Chukotka
Chuquisaca
Colombia - Civil Ensign
Colombia - Naval Ensign
Colorado
Comoros
Comoros (1975-1978)
Cook Islands
Costa Rica
Costa Rica - State Flag
Crimea
Croatia
Croatia - Civil Ensign
Croatia - Naval Ensign
Cuba