Pyperclip - Super easy cut and paste to clipboard in python, multi OS - Advent of Code 2021
This library is so handy when dealing with large chunks of data, or complicated things that I don't want to mess up selecting - fill the os's paste buffer (or get it from) in a single line of code. And Pyperclip gets better as its cross-OS, i.e this works on Windows, Macs and Linux equally as well as each other.
There's very little I can say about Pyperclip because it's such a short library - it does have one sort of hidden feature (that's in the docs just not on its homepage) which is a wait feature that allows it to trigger a flow when a new thing is copied on the OS clipboard.
I love this tool, and it's one of the things that I use occasionally because it's more for those interactive programs rather than servers or service applications.