Yellow rarely carries a flag on its own, almost no national flag is majority yellow, but it shows up constantly as a supporting color, and what it stands for shifts depending on where you look. In Africa, yellow is part of the pan-African palette, standing for mineral wealth and the sun. In Latin America, it traces back to Gran Colombia’s tricolor and often represents natural riches or sovereignty. Elsewhere it tends to mark gold, wealth, or the sun directly.
Pan-African colors, mineral wealth and the sun
Senegal · Mali · Guinea · Ghana · Cameroon · Benin · Togo · Burkina Faso · Zimbabwe · South Africa · Gabon · Congo, Democratic Republic of the · Mozambique · Central African Republic · Zambia
Gran Colombia heritage
Venezuela · Colombia · Ecuador
Gold, sun, and mineral wealth elsewhere
Spain · Romania · [Vatican City, not currently on the site] · Sweden · Ukraine · Brazil · Argentina · Uruguay · Kazakhstan · China · Vietnam · Nepal · Bhutan · Malaysia · Sri Lanka · Cambodia · [Vatican City, not currently on the site]
Everywhere else yellow shows up prominently
Germany · Belgium · Lithuania · Moldova · Barbados · Jamaica · Suriname · Micronesia