I use git worktrees pretty heavily in my own workflows (I worked like an AI agent before AI agents made worktrees cool). I like to track my ephemera/utility scripts in git, so what I do is keep a private ephemera repo for those, and then use `git worktree add` from the collaborative repo to check out the branch I'm working on there into a subdirectory of my ephemera repo.

  git-home/
    company-project/ <-- git repo with main checked out
    ephemera/ <-- my private repo
      my-data-script.py
      work/ <-- gitignored
        company-project-feature-X/ <-- worktree on feature-X branch
        company-project-feature-Y/ <-- worktree on feature-Y branch
      

This way, too, I can easily use the same ephemera scripts across multiple branches, or even multiple repos, concurrently.