This makes the list autoplay toggle actually work; i.e., it is now a global setting rather than per-page clickfest.

youtubefix2

// ==UserScript==
// @name       YouTube Autoplay Toggle
// @namespace  https://gist.github.com/k98kurz
// @updateUrl  https://gist.githubusercontent.com/k98kurz/76c08ff2dbe0a479c955/raw/
// @version    1.2
// @description  This makes the list autoplay toggle actually work; i.e., it is now a global setting rather than per-page clickfest.
// @match      https://www.youtube.com/watch?v=*&list=*
// @match      http://www.youtube.com/watch?v=*&list=*
// @match      https://www.youtube.com/watch?list=*&v=*
// @match      http://www.youtube.com/watch?list=*&v=*
// @copyright  2014+, me
// ==/UserScript==

(function (w) {
    // wait until the DOM is loaded
    document.addEventListener("DOMContentLoaded", function () {
        // and then wait some more (because of weird youtube ajax stuff)
        setTimeout( function() {
            var t = document.querySelector(".toggle-autoplay");
            // automatically turn off autoplay if it has been toggled appropriately
            if (localStorage.disableAnnoyingAutoplay=='true'&&t.attributes['class'].value.indexOf('yt-uix-button-toggled')>=0) {
                t.dispatchEvent(new MouseEvent("click"));
                t.attributes['class'].value = t.attributes['class'].value.replace(' yt-uix-button-toggled', '');
            }
            
            // toggle setting
            t.addEventListener("click", function(e) {
                localStorage.disableAnnoyingAutoplay = (localStorage.disableAnnoyingAutoplay=='true' ? 'false' : 'true');
            });
        }, 1000);
    });
})();