If you want to squeeze as much out of your input to get the best results out of AI models like Midjourney, PromptPerfect is worth a look. It's geared specifically for optimizing prompts for large language models like GPT-4 and ChatGPT, so you can get the best results as fast as possible. If you find that fine-tuning prompts is an important part of getting what you want out of AI, this tool is well worth a look.
Another option is OctiAI, which has a more advanced prompt generation system for image and text tasks. It supports more than 15 of the biggest AI models, including Midjourney, and has features like prompt optimization, cross-platform support and an AI community for collaboration. With OctiAI, you can fine-tune prompts and otherwise try to squeeze more out of AI.
If you want a broader approach, Freshly.ai tries to marry human creativity with AI tools to boost productivity and creativity. It has a variety of tools, including a prompt optimization tool and an AI-powered prompt optimizer, that you can use to try different approaches to get the best out of your AI. Freshly.ai is geared for people who want to explore the potential of AI without necessarily having a lot of technical expertise.
Finally, LastMile AI is a full-stack developer platform to let engineers get generative AI applications into production as quickly as possible. It includes tools like prompt optimization, automated hallucination detection and a notebook-like environment for prototyping and app development. It's geared for developers who want to get AI applications into production as quickly as possible.