Very nice list of bash-internal functionality. Mirrors the 'pure-sh-bible' by dylanaraps.

Automatically upgrade your Polars code to use the latest syntax available. Run over python polars code and it switches out deprecated stuff for up-to-date stuff. Simple, easy, nice.

Hold presentations with a projector connected (i.e. dual-screen) - you get to read notes you prepared and see the current and upcoming slide in a little side-window while the big screen just sees the current slide.
I think slide.js/reveal.js has a similar feature that can be activated with a key combination but this has it baked in