Common words:
* Democrat
* Republican
* Autocrat
* Technocrat
* Bureaucrat
* Aristocrat
* Plutocrat
Less common words:
* Theocrat
* Biblioclast
* Stratocrat
* Democratist
* Ethnocrat
* Feudocrat
* Gerontocrat
* Logocrat
* Meritocrat
* Nomocrat
* Oligocrat
* Patriarch
* Populocrat
* Sophocrat
* Technocratist
Note:
The "-crat" suffix generally refers to a person who believes in or advocates for a specific type of rule or government.