Here are some free AI tools that can be useful for artists and designers:

1. DeepArt.io: This tool allows you to transform your photos into artwork using various artistic styles and neural networks.

2. RunwayML: It offers a range of AI models and tools for creative projects, including image generation, style transfer, and text-to-image synthesis.

3. ArtBreeder: It combines the power of machine learning with your artistic input to create new and unique images by blending and evolving existing artworks.

4. Google Deep Dream: Originally developed to visualize the inner workings of neural networks, Deep Dream can be used to generate psychedelic and surreal images by applying deep learning algorithms to existing photos.

5. Canva: While not solely an AI tool, Canva provides a user-friendly interface with AI-powered design assistance, helping artists and designers create visually appealing graphics, social media posts, and more.

6. Adobe Sensei: Adobe's suite of creative tools incorporates AI capabilities through Adobe Sensei, assisting artists and designers in various tasks, such as auto-selecting subjects, enhancing images, and generating color palettes.

7. Doodle3D Transform: This tool allows you to transform 2D drawings into 3D models. While it doesn't use AI directly, it can be a helpful tool for artists interested in exploring the realm of 3D design.

8. OpenAI DALL-E: Although not a standalone tool, OpenAI's DALL-E is an AI model capable of generating images from textual descriptions. The model has been used by artists and designers to create unique visual concepts.

These tools can be a starting point for artists and designers to explore the creative possibilities offered by AI. Remember to review the terms and conditions of each tool to understand any limitations or usage restrictions.