General:
* Narrator
* Chronicler
* Bard
* Minstrel
* Griot
* Fabulist
* Mythmaker
* Wordsmith
* Tale-spinner
More formal:
* Historian
* Biographer
* Novelist
* Writer
* Author
Informal:
* Yarnspinner
* Spin doctor
* Storyteller (although this is also a synonym!)
The best synonym will depend on the specific context and the tone of your writing. For example, "bard" might be a good choice for a story set in medieval times, while "spin doctor" might be more appropriate for a news article about a politician.