For my personal notes, I use Smart Connections[1] with Obsidian. Since the notes are stored in plain markdown files, I am considering devising my own solution using LlamaIndex[2] in the near future.
For coding, I use Copilot[3]. While it's been great for writing boilerplate code, it falls short in every other regard. I also had the opportunity to try the new version of Copilot as well, but it feels like a glorified ChatGPT inside VSCode.
For everything else, I use a tiny tool I made[4] which enables me to invoke my own prompts in basically any application that allows me to select text.
[1] https://github.com/brianpetro/obsidian-smart-connections
[2] https://gpt-index.readthedocs.io/en/latest/getting_started/s...