George RR Martin could have written more novels about the Targaryens after publishing Fire & Blood if only he had more time.
George RR Martin on the Battle of the Trident
Game of Thrones fans are already frustrated with George RR Martin's still-unfinished The Winds of Winter, and they may be even more angry when they learn that there are more stories for him to explore. Unfortunately he is not getting any younger so they will now remain unwritten and unpublished.
In 2018, Martin released Fire & Blood, the story of the Targaryens who ruled the seven kingdoms of Westeros. Within the novel are several accounts chronicling the adventures, glories and defeats of not only royalty but also other notable figures. In short, there were stories within stories.
It's no secret why George RR Martin hasn't finished writing The Winds of Winter. He's busy with so many other things, including producing several Game of Thrones spinoffs, but he was able to write Fire & Blood while the HBO series was still running.