Bonus points to anyone who can name all those countries without doing research because you already have all the world’s country flags memorized.

I sure can’t.

EU, Chad, PRC, ?Guyana?, Brasil, ?Portugal?, Bermuda, ???, Bulgaria, Jamaica, South Africa, Kosovo, ???, Saudi Arabia, ?Botswana?, ???, ???, Cuba, Greece, ???.

How did I do?

EDIT: Kosovo was one of the ???

Guyana, yes
Yes, Portugal
Did not know Bermuda
Not Bulgaria, but Hungary
Not Kosovo but Bosnia and Herzegovina
The Seychelles
Not Botswana 🇧🇼 but Tanzania 🇹🇿
That’s Kosovo
São Tomé and Principe (or maybe St. Kitts and Nevis)
Timor-Leste

After Bosnia is apparently the Christmas Island, a territory of Australia. (Seychelles are a above it.)

The flag has a bit unusual proportions of 1:2.