Nat.dev open playground is an LLM playground that you can run on your laptop or try online. It lets you use any model from OpenAI, Anthropic, Cohere, Forefront, HuggingFace, Aleph Alpha, Replicate, Banana and llama.cpp.
You can also compare models side-by-side with the same prompt, individually tune model parameters, and retry with different parameters.
You can also try GPT-4 for free on Open Playground.
Open Playground:
https://nat.dev
ChatGPT:
https://www.futurepedia.io/tool/chatgpt