These aren't for ChatGPT, but work on LLaMA, Vicuna, etc.

https://github.com/oobabooga/text-generation-webui/blob/main...

https://github.com/zetavg/LLaMA-LoRA-Tuner

https://github.com/h2oai/h2o-llmstudio

https://github.com/rhulha/lora

If you're running the text-generation-webui (https://github.com/oobabooga/text-generation-webui) it has the ability to train LoRAs.

It'll require a beefy GPU but I've seen some fun examples like someone training a LoRA on Skyrim books.