Obsidian GPT is a plugin for Obsidian.
It allows for the use of large language models such as GPT-3 within obsidian. You can use the current line or highlighted text to request a completion from models such as:
It was later rewritten to use OpenRouter as a provider, but I am not actively maintaining it anymore.
As far as I know was the first LLM plugin ever available for Obsidian.