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!
BloatyNosy
https://github.com/builtbybel/BloatyNosy
sleek
https://github.com/ransome1/sleek
WinDirStat
https://github.com/windirstat/windirstat
MacType
https://github.com/snowie2000/mactype
In my experience, windirstat is inferior to other similar software. It’s mostly fine but it can be very, very slow to get you results. Though honestly I don’t know if the alternatives like space sniffer or Wiztree are open source.
FileLight from KDE also works on Windows
They're both closed source.
gdu is in winget, and it's extremely fast.
I dont get mactype there simply is no explanation what it does?
Yeah, the documentation is very sparse. I think it was originally all in Simplified Chinese, but some things have been translated to English. Basically it gives you tools to fix subpixel font rendering issues on windows. Using a rotated monitor? An OLED monitor? A TV? All of these are examples of screens that don't have standard subpixel layouts, so fonts tend to have weird color fringing as a result. MacType allows for a lot of tweaks to how fonts are rendered, but I tend to just switch to grayscale rendering, which works well.
This reddit thread walks through the process with some specific configs and they have pictures to show how it changes things.
https://www.reddit.com/r/OLED_Gaming/comments/t30fi7/better_text_rendering_for_oled_displays_getting/