Free AI (Artificial Intelligence) tools are widely available and can be a great starting point for exploring artificial intelligence. Here’s a list of top free AI tools with their features as of my last knowledge update in January 2022:

1. TensorFlow: An open-source machine learning framework developed by Google. It provides a wide range of tools for building and training machine learning models, including deep neural networks.
2. PyTorch: An open-source deep learning framework developed by Facebook’s AI Research lab. PyTorch is known for its dynamic computation graph and is particularly popular for deep learning research.
3. Scikit-Learn: A simple and efficient tool for data analysis and modeling. It offers a wide variety of machine learning algorithms and is great for beginners in AI.
4. Keras: A high-level neural networks API that runs on top of TensorFlow or other deep learning frameworks. Keras simplifies the process of building and training neural networks.
5. Jupyter Notebook: Jupyter is an open-source web application that allows you to create and share documents that contain live code, equations, visualizations, and narrative text. It’s widely used for data science and AI research.
6. DeepAI: DeepAI offers various AI models and tools for tasks like image generation, text generation, and more. It’s known for its user-friendly web interface.
7. Google Colab: Google Colab is a cloud-based platform that provides free access to GPUs and TPUs. It’s popular for running Jupyter notebooks in the cloud, making it easy to experiment with AI models without needing a high-end GPU locally.
8. Fast.ai: Fast.ai is an open-source deep learning library that simplifies the training of neural networks. It includes a free deep learning course that’s known for its practical approach to AI education.
9. Microsoft Azure Machine Learning Studio (Free Tier): Microsoft Azure offers a free tier for its Azure Machine Learning Studio, allowing you to create and deploy machine learning models with a limited set of features. It’s a good choice for experimenting with Azure’s AI capabilities.
10. OpenAI GPT-3 Playground (Limited Access): OpenAI’s GPT-3 Playground provides limited access to the GPT-3 language model. You can experiment with the model for tasks like text generation, question answering, and more.

Remember that while these tools are free, some may have usage limitations or offer paid versions with additional features and resources. Always check the terms of use and the specific limitations of the free versions when using these tools for AI projects. Additionally, the AI landscape is dynamic, so new free tools and updates to existing ones may have emerged since my last update.