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!
Ventoy is easy, but not perfect. I tried multum of unique images and it struggled hard. From openwrt to freedos to reboot of Hiren's boot cd, it just couldn't load them correctly.
Not to be argumentative, but in case you're interested:
According to the ventoy site it supports those images, though openwrt requires a plugin and freedos seems to require using memdisk mode, though I'm less clear on the limitations there.
Oh, I didn't know that, but still, I don't expect to be truly universal. But as long as you are dealing with ISOs of LX server/desktop or WIN, it's an amazing tool.