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!
GIMP (Image editor)
putty (Secure shell/terminal emulator)
WinSCP (Secure FTP client)
QBittorrent (guess.)
7zip (All in one compressed archive manager)
Firefox
Notepad++ (text editor with syntax highlights)
Handbrake (Video transcoder)
VLC (all in one video player)
These are my top must have installed. There are others but they're situational
Let's not forget the various console emulators that are open source as well. All the good ones are.
I use Kitty instead of Putty recently, though I don't know if the difference is worth it.
I just use Powershell, much easier imo