Would it be possible to add a minimalistic image that contains app, kernel and essential packages? Like what you would get when building a docker container or using the not-os repo that I mentioned earlier.

I think having mini images would be awesome.

You might like: https://nixery.dev/

e.g. if you want a Nix container with a shell environment, git, and htop:

    docker run -ti nixery.dev/shell/git/htop bash