A flag enthusiast is commonly referred to as a "vexillophile." This term comes from the Latin word "vexillum," meaning flag or banner, and "phile," meaning lover of. Vexillophiles often collect flags, study their history, and appreciate their designs and symbolism.
A ballet enthusiast is called a "balletomane".
A collector of certificates, a certificate enthusiast!
The California flag is called the bear flag.
It is called "Red Ensign". The Ontario's flag is called "Red Ensign".
A person who studies a lot is often called a "bookworm" or a "knowledge enthusiast."
A flag specialist is called a vexillologist.
A knight's flag is called a Pennon. It is a small flag on end of lance.
The "field." The horizontal length of the flag is called the "fly." The height of the flag is called the "hoist."
A Flag
Such a flag is called a national flag.
a flag maker is called a bing bong beggar
pennant or pennon