Flags featuring blue and yellow colors

Dover

city in Delaware, USA

Dublin

city in Ireland

Dubrovnik-Neretva County

county in Croatia

Dunajskà Streda

municipality in Slovakia

Ecuador

country in South America national flag

Ecuador

country in South America civil flag

El Salvador

country in North America national flag

El Salvador

country in North America civil ensign

Equatorial Guinea

country in Africa national flag

Eritrea

country in Africa national flag

Erlinsbach

municipality in Aarau District, Aargau, Switzerland

Estonia

country in Europe commander in chief flag

Estonia

country in Europe lieutenant general flag

Estonia

country in Europe major general flag

Estonia

country in Europe naval ensign

Estonia

country in Europe presidential flag

Estonia

country in Europe rear admiral flag

Estonian SSR

republic in Soviet Union (1953-1990)

Eswatini

country in Africa national flag

Ethiopia

country in Africa national flag

European Union

Extremadura

autonomous community in Spain

Falcón

state in Venezuela

Falkland Islands

territory and overseas territory of UK in South America