Open source library for apps to use any LLM

Any of you considering running multiple LLMs or writing plugins from your apps to multiple LLMs? Trying to validate a hypothesis I have for an open-source project I’m considering pouring some time into:
A library that would enable an app to work with all the major LLMs (OpenAi, Bard etc.)

Thanks for asking GPT. I’m curious about people who are building. Thanks though!