Question: Is there a service that allows me to write a book in multiple genres, such as romance, horror, and sci-fi?

If you want to use the tool to write a book that spans multiple genres -- romance, horror and sci-fi, for example -- AuthorGPT is a good option. The AI tool can generate full-length books in Fantasy, Sci-Fi, Romance, Horror and other categories. It's geared for people who want to dabble in creative writing and those who want to become novelists, with options to set settings and characters to help you craft a story.

Another option is NovelistAI, which offers a variety of tools to generate custom novels, non-fiction books and interactive storybooks. It works in more than 30 languages and can generate entire stories, including gamebooks and novels. You can customize your books with cover images and audiobook versions, too, making it a good option for a broad range of literary output.

Scene One is cloud-based novel writing software with a stripped-down text editor and a variety of tools to manage scenes and projects. It has tools to track word count, generate writing prompts with AI assistance, and create a custom wiki to flesh out your story world. It's geared for romance, sci-fi and fantasy novelists who want to use AI to help boost productivity.

If you want more control, try NovelAI. The service uses AI for authorship and storytelling, so you can write literature with no restrictions. It comes with image generation tools for character visualization, a text adventure module for interactive fiction and a customizable editor. With several pricing tiers, it's an option for writers who want to pay for what they need and can afford it.