What are some of your favourite small apps?

One of my recent past-times is making small command-line applications in Python to address some small task I think can be automated.

(you can find some of them pinned here.)

On the other hand, lately I've been loving to use scli, a terminal Signal client.

Every so often I find such relatively little known but super cool terminal app projects on github. But, it seems like I only find these when I go looking for something very specific.

So, I'm looking for recommendations: npm or pip executables that are relatively simple in their functionality, but fill some gap usefully.

I can start:

glow is great for markdown in the terminal.