I am and all my life have been a Linux user, I have nothing against Windows or MacOS, I just like Linux, and lately I have been experimenting with Windows in a virtual machine and I don’t really know much open source software there apart from the one that is cross-platform like Firefox or Joplin.
At the moment I know:
Flow Launcher: It’s a typical rofi style launcher, although I’m not a TWM user I like to just press super and type the first letters of the program I’m looking for to open it.
Lively Wallpaper: A program to have animated wallpapers, in the style of Wallpaper Engine.
Edit: I want to clarify that I read all the comments, I only respond to some because many times I have nothing to contribute to many of them because I don’t know what to comment. Thanks to all of you for providing your lists of programs, I will be sure to try as many as I can because they are great, at least I know what to install if I use Windows one day!
Xoblite: Blackbox/Fluxbox-style WM/shell for Windows.
Open Shell: Brings back the classic start menu and other classic Explorer.exe features
Notepad2e: A lightweight and portable alternative to Notepad++
AutoHotkey: Probably the best GUI automation tool out there, this is the tool that I miss the most in the Linux world.
There’s also Kate, the KDE Advanced Text Editor. It’s available from the Windows store, and works amazingly well on Windows, fast snappy and (almost?) just as featurefull as on Linux. I use it side by side with Notepad++