DeepFiction is an AI story generator that turns prompts into stories, videos and photos in a variety of styles, tones and settings. It's got modules like a movie pitch generator and a fan fiction generator, and you can set preferences while still maintaining some freedom of expression. DeepFiction has three service tiers, so you can pay to explore an unlimited number of AI-created stories for entertainment, marketing or self-expression.
Another strong contender is NovelAI, which uses an AI model trained to write in your style and voice. It's got a text adventure module for interactive fiction, an editing module you can customize, and an image generation module for character visualization. NovelAI has four pricing tiers, so you can pay what you need, and it's a powerful tool for creative writing.
If you prefer a more collaborative approach, StoryNest.ai has a range of tools for creating stories, novels and interactive narratives. It's got character creation and world-building tools, AI-assisted editing, and voice narration. It's free to try, and it can handle a range of formats, including interactive fiction and nonfiction, so it's good for a broader range of writers.
Last, InstaNovel is geared for short novels with a minimal amount of user input. You can enter a single prompt and select an art style, and InstaNovel will send you a four-to-six chapter book by email. InstaNovel uses GPT-3 for the text and Dall-E 2 for the visual style, so it's a good way to get ideas and learn how these tools work. It only works in English for now, but it plans to expand to other languages.