Allows you to completely reload the YouTube page and start where you left off. Create a shortcut and enter this into the "URL" field.

refresh-youtube

javascript: (function () {
var re = window.location.href.match(/v=([^\?&"'>]+)/g);
if (re && re.length > 0) {
  window.location='https://youtu.be/' + re[0].split('=')[1] + "?t=" + Math.round(document.getElementById('movie_player').getCurrentTime()); 
}
})();