Anthropic have released a prompt generator:
Automatically generate first draft prompt templates
Sometimes, the hardest part of using an AI model is figuring out how to prompt it effectively. To help with this, we’ve created a prompt generation tool that guides Claude to generate high-quality prompt templates tailored to your specific tasks. These templates follow many of our prompt engineering best practices.
The prompt generator is particularly useful as a tool for solving the “blank page problem” to give you a jumping-off point for further testing and iteration.