I'd say Kate

You won't find a 100% replacement because npp has a bunch of very specific plugins, but often those plugins would be unnecessary on Linux because you already have other utilities that perform those jobs. You don't need a plugin to ssh into a server to edit files when you've got sshfs for example.

Anyway you can use Geany on Gnome or Kate on KDE.

Depends on what you want to do. I'm a dirty vim user and use nvim in the terminal. There are a lot of text editors though.

Kate is grate

There are better text editors. Swearing by that one is kind of a joke.

If its the ui you are looking for there is notepadqq

A must-be joke: vim

And seriously, Sublime

I use Zed Editor on a daily basis even though they push AI in it (it's purely opt-in, thankfully)

For alternative software, I usually ask AlternativeTo : https://alternativeto.net/software/notepad-plus-plus/?platform=linux&license=opensource

Edit: Some people seem to disagree and I'd like to know if it's related to Zed, AI in Zed or AlternativeTo, thanks in advance!

Geany