General Synonyms:
* Sovereign
* Nobility
* Aristocracy
* Blue blood
* Highborn
* Monarchy
* Regal
* Imperial
* Royal family
* The Crown
More Specific Synonyms:
* King/Queen (specific rulers)
* Prince/Princess (members of the royal family)
* Duke/Duchess (nobles with high rank)
* Earl/Countess (nobles with lower rank)
* Baron/Baroness (nobles with the lowest rank)
* Hereditary (relating to inheritance of royal status)
Figurative Synonyms:
* Majesty (expressing respect and awe)
* Eminence (high status and importance)
* Magnificence (great splendor and grandeur)
* Excellence (superior quality and achievement)
* First-rate (of the highest quality)
The best synonym to use will depend on the specific context of your writing.