Half of these exist because I was bored once.
The Windows 10 and MacOS ones are GPU passthrough enabled and what I occasionally use if I have to use a Windows or Mac application. Windows 7 is also GPU enabled, but is more a nostalgia thing than anything.
I think my PopOS VM was originally installed for fun, but I used it along with my Arch Linux, Debian 12 and Testing (I run Testing on host, but I wanted a fresh environment and was too lazy to spin up a Docker or chroot), Ubuntu 23.10 and Fedora to test various software builds and bugs, as I don't like touching normal Ubuntu unless I must.
The Windows Server 2022 one is one I recently spun up to mess with Windows Docker Containers (I have to port an app to Windows, and was looking at that for CI). That all become moot when I found out Github's CI doesn't support Windows Docker containers despite supporting Windows runners (The organization I'm doing it for uses Github, so I have to use it).
I have a real use case! I have a commercial server software that can run on Ubuntu or RHEL compatible distributions. My entire environment is Ubuntu. They also allow the server software to run in a docker container but the container must be running RHEL. Furthermore, their license terms require me to build the docker container myself to accept the EULA and the docker image must be built on RHEL! So I have an LXC container running Rocky Linux that gets docker installed for the purpose of building RHEL (Core is 8) imaged docker containers. It’s a total mess but it works! You must configure nested security because this doesn’t work by default.
Instructions here: https://ubuntu.com/tutorials/how-to-run-docker-inside-lxd-containers#1-overview