AIPRM has a large library of more than 70,000 private and 4,500 public prompts. It's geared for managing, creating and repurposing prompts, so it's good for maintaining a consistent voice for your brand. It has features like prompt management, custom tone and writing style, and a verified prompts system.
Another good option is PromptDrive, which offers a full prompt management system. You can create, share and refine prompts with a web app and features like chat AI collaboration, organization tools and variables for prompts. It also offers a Chrome extension for quick access in supported AI tools.
If you prefer community-based options, Snack Prompt lets you find, upvote and share prompts that work well with ChatGPT and Gemini. By tapping into a community of people who've honed prompt creation, you can get good AI results in your area of interest. The site's topic following feature will give you related prompts.