Neurochat is a opensource native GUI for OpenAI LLMs, LLama.cpp and the free service neuroengine.ai.

It's basically an opensource version of LLMStudio. Currently it works on Windows and Linux, and I have some experimental builds for MacOS too. Apart from being 100% native (using FreePascal) is that with an API key you can access ChatGPT4 using this GUI without having to do monthly payments, you only pay for whatever you use. This is quite useful for me as I don't use GPT4 enough to justify the monthly payments, but I still want to try it once in a while.

It supports local LLMs out-of-the-box using LLama.cpp dll and you can use GPU acceleration if you provide the corresponding accelerated LLama.cpp build for your system.