Formal:
* Sovereign: Emphasizes the ruler's power and authority.
* Monarch: A more general term for a king or queen.
* Regent: Used when a queen is acting as the ruler in place of a king.
* Empress: Used for the queen of an empire.
Informal:
* Royal: A general term referring to the queen's status.
* Majesty: A respectful title for a queen.
* Your Highness: A formal address for a queen.
* Lady: A less formal term, but can be used to refer to a queen in some contexts.
Figurative:
* Matriarch: A powerful female figure who heads a family or group.
* Queen Bee: A dominant female figure in a group or organization.
The best word to use will depend on the specific context and the tone you are trying to convey.