What was the best theme for a novel was a very subjective question because everyone had different opinions about the "best" theme. However, according to the common techniques and trends of online writing, the following are some topics that might be suitable for writing novels: Love: Love is a very popular topic that can involve romance, drama, bitterness, sweetness and other different types of emotions. Adventure: Adventure novels usually involve exploring unknown areas, facing challenges and difficulties, and discovering new opportunities and resources. 3. Adulthood: Initiation stories usually involve the protagonist gradually becoming stronger, more confident, and more mature through various difficulties and challenges. Science fiction: Science fiction usually involves the exploration of the future of mankind, the advancement of science and technology, and the challenges and opportunities faced by mankind. Fantasy: Fantasy novels often involve myths, magic, monsters, treasures, and other fantasy elements that allow readers to experience different cultures, histories, and traditions. Of course, these were only some of the most suitable topics for writing a novel. The most suitable topics needed to be considered according to the story, the plot, the target audience, and other factors.