For creating story outlines and character sheets, Novelcrafter is a great option. It's a full featured writing environment with a personal Wiki for storing story information, multiple writing modes, and AI tools. The Codex feature is useful for tracking characters, locations, and other story elements, and it's good for both planners and pantsers. Novelcrafter also has a range of outlining and revision tools, and it lets you label and tag elements with your own tags and labels.
Another option is Subtxt, which uses AI to help writers construct the narrative structure and consistency of a story. It includes tools like Narrative Agents for important story beats, Subtxt Muse for developing the story, and Storyforms for more advanced analysis. Subtxt is geared for screenplays, novels and plays, and it offers different pricing levels, including a basic $25/month plan and a more advanced Pro plan at $45/month.
LivingWriter is also worth a look. It's a clean interface for organizing manuscripts with more advanced features like an AI Outline Generator, smart text suggestions, writing goals and export options. It's cloud based, so it synchronizes across multiple devices, and it's a good option for authors who want to get their work organized.
Last, Sudowrite uses AI to help with idea generation, outlining and writing. It's got tools like Story Bible for character development, Write and Expand for advancing the plot and Rewrite for editing text. With customizable modes and project organization tools, Sudowrite is designed to help you be more creative and productive, and it's good for fiction authors at any stage of the process.