original link by @joyblanks https://gist.github.com/jordan314/6bdc9af962fd8620a4fb#gistcomment-3128172

netflix my list export import

1. Login & Select your old Account -> Profile
2. Go to My List (old profile)
3. Run this code in your Browser Developer console to Export and save My List

var tmpList = (function() {
    var list = []
    document.querySelectorAll('.title-card a[aria-label]').forEach(
        function(item) {
            try {
                list.push({
                    name: item.getAttribute('aria-label'),
                    link: ("https://www.netflix.com" + item.getAttribute("href").split("?")[0]).replace('watch', 'title')
                })
            } catch (err) {
                console.error("ERROR: Ignored err", err, item)
            }
        })
    return (JSON.stringify(list));
}());
localStorage.setItem('tmpList',tmpList);
4. Logout old account
5. Login & Select your new Account -> Profile
6. Run this Code in your Browser Developer console to Import My List saved in step 3

(function(){
  var list = JSON.parse(localStorage.getItem('tmpList'))
  var counter = 0;
  function openWin(e){
    var popup;
    popup = window.open(list[e].link);
    popup.onload = function(){
      setTimeout(function(){
        if(popup.document.querySelector('.nf-flat-button-icon-mylist-add + span')){
          popup.document.querySelector('.nf-flat-button-icon-mylist-add + span').click();
          setTimeout(function(){popup.close()}, 500);
          console.log('Added', list[e].name);
        } else {
          popup.close();
          console.log('Already added', list[e].name);
        }
      }, 500)
    }
    var timer = setInterval(function() { 
      if(popup && popup.closed) {
        clearInterval(timer);
        if(list.length-1 > counter){
          openWin(++counter);
        } else {
          console.log('Added');
          localStorage.removeItem('tmpList');
        }
      }
    }, 1000);
  }
  openWin(counter)
}())
7. Done