The main character is probably the king, as the name 'king gold story' implies. There could also be a character who tries to steal the king's gold. Maybe there is a magician or a thief who plays an important role in the story. Another possible main character could be a poor person whose life gets affected by the king's gold, either in a positive or negative way.
In the 'king gold story', the king is surely a main character. If it's a story about the king's journey to obtain gold, there could be companions or guides who accompany him. There might be a rival king who also desires the gold. And perhaps there is a wise old man or a prophet in the story who gives advice regarding the gold, its value, and its consequences.
Well, the Gold King is obviously one of the main characters. There might also be his advisers, like an old and wise man who has been with him since his early days. His enemies are also important characters, perhaps a rival king or a powerful sorcerer who wants to dethrone him.
Since I haven't read the specific gold coin story, I can only guess. There could be a protagonist, perhaps a young adventurer who discovers the gold coin during his journey. There might be an antagonist, like a cunning old miser who wants to take the gold coin away from the adventurer. And there could be other supporting characters such as the innkeeper where the adventurer stays and who gives him some advice about the gold coin, or a wise old man in the village who knows the true value and the history of the gold coin.
In some 'city of gold stories', there could be local guides or natives who play important roles. They might know some secrets about the location of the city. The main characters also could include greedy conquistadors who were more interested in looting the gold than understanding the culture of the place. And sometimes, there are wise elders in the story who try to protect the city of gold from being discovered by the wrong people.
Since I don't know the exact 'gold watch story', it's hard to say. But it could be a grandfather who owns the gold watch and his grandson who inherits it.
As I don't know the specific 'gold a true story', I can't say who the main characters are.
The main characters are Maria Altmann and Randol Schoenberg. Maria Altmann was the woman who fought to reclaim the 'Woman in Gold' painting as it was of her aunt. Randol Schoenberg was the lawyer who helped her in this legal battle.
I'm not sure as I haven't read the 'Heart of Gold' short story. But typically in a story with such a title, there might be a protagonist who is known for their kind - heartedness or has some connection to the 'heart of gold' concept.
Maria Altmann is a main character as she is the one fighting for the painting.
Since I don't know the exact 'little gold star story', it's hard to say. But it could be the little gold star itself as the main character.
Then there is the unnamed narrator. He is Legrand's friend and is the one who tells the story from his perspective. He is involved in the events and helps to piece together the mystery of the gold.