David's talks at PyCon are all amazing. My favorite is this one: https://www.youtube.com/watch?v=MCs5OvhV9S4

Funny enough, a few months ago we decided to start a new project and we chose async Python. I had no clue how'd work so I decided to read the PEP and learn a bit more. Big was my surprise when I realized I "knew" all the fundamentals just by understanding how coroutines and generators worked low level, thanks to David's talks.

EDIT: His talks about the GIL are also super informative!