YouTube Ads Disabler (com.vsubhash.js.youtube-ads-disabler) is a User Javascript for YouTube that will automaticaly disable ads, switch off autoplay, add RSS feeds, remove "Recommended for you" video, unhide description and display latest comments.

com.vsubhash.js.youtube-ads-disabler

// ==UserScript==
// @name        YouTube Ads Disabler
// @namespace   com.vsubhash.js.youtube-ads-disabler
// @description Disables ads, swithces off autoplay, adds RSS link, deletes "recommended for you" videos, unhides description, displays latest comments
// @include     https://www.youtube.com/watch*
// @version     1
// @grant       none
// ==/UserScript==

try {
  window.setTimeout(
    function() {
      document.getElementsByTagName('video')[0].pause();
      document.getElementsByTagName('video')[1].pause();    
    }, 
    5*1000);
} catch (e) {
  console.error("YAD Error: " + e);
}


document.addEventListener("DOMContentLoaded", fixYouTubeAnnoyances, false);
  

function fixYouTubeAnnoyances() {
  console.log("YAD: Here");
  var sAdStyle = " { visibility: none!important; display: none!important; }";
  
  
  try {
    window.setTimeout(closeVideoAds, 1*1000);
    window.setTimeout(showDescription, 2*1000);
    window.setTimeout(removeRecommendedForYouAds, 3*1000);  
    window.setTimeout(disableAndHideAdContainers, 4*1000);  
    window.setTimeout(disableAutoPlay, 5*1000);
    
  } catch (e) {
    console.error("YAD Error: " + e);
  }
}

function closeVideoAds() {
  console.log("YAD: Detecting video ads...");        
  if ((document.getElementsByClassName("videoAdUiTopButtons").length > 0) || (document.getElementsByClassName("videoAdUi").length > 0)) {
    
    console.log("YAD: Video ad found");      
    window.open(location.href, '_blank');
    //window.open(location, '_self').close();
    window.close();

    if (document.getElementsByClassName("ytp-mute-button").length > 0) {
      console.log("YAD: Video ad mute button found");        
      if (document.getElementsByClassName("ytp-volume-panel").length > 0) {
        if (document.getElementsByClassName("ytp-volume-panel")[0].getAttribute("aria-volumetext") != "100% volume muted") {
          document.getElementsByClassName("ytp-mute-button")[0].click();            
          console.log("YAD: Video ad muted");
        }
      }
    }      

  } else {
    console.log("YAD: No video ad");
  }
}


function disableAutoPlay() {
  console.log("YAD: Disabling autoplay...");
  var arAutoPlayIds = [ "toggleButton", "autoplay-checkbox" ];
  for (var i = 0; i < arAutoPlayIds.length; i++) {
    console.log("YAD: Checking for autoplay ID " + arAutoPlayIds[i]);
    if ((document.getElementById(arAutoPlayIds[i]) != null) && (document.getElementById(arAutoPlayIds[i]).checked)) {
      console.log("YAD: Aautoplay ID found " + arAutoPlayIds[i]);
      document.getElementById(arAutoPlayIds[i]).click();  
      console.log("YAD: Autoplay ID disabled - " + arAutoPlayIds[i]);
    }    
  }
}

function showDescription() {
  console.log("YAD: Finding description...");
  if (document.getElementById("action-panel-details") != null) {
    document.getElementById("action-panel-details").className = "action-panel-content yt-uix-expander yt-card yt-card-has-padding";
  }
  console.log("YAD: Description unhidden.");
}

function removeRecommendedForYouAds() {
  console.log("YAD: Removing recommended videos");
  var oRelatedColumn = document.getElementById("watch-related");
  if (oRelatedColumn != null) {
    var arRelatedVids = oRelatedColumn.getElementsByTagName("li");
    var j = 0;
    if (arRelatedVids.length > 0) {
      for (var i = arRelatedVids.length-1; i > -1; i--) {        
        if (arRelatedVids[i].textContent.indexOf("Recommended for you") != -1) {
          //console.log("YAD: Removing " + arRelatedVids[i].textContent);
          arRelatedVids[i].parentNode.removeChild(arRelatedVids[i]);
          ++j;
        }
      }
    }
    console.log("YAD: Removed " + j  + " recommended videos");      
  }
}

function disableAndHideAdContainers() {
  console.log("YAD: Disabling/deleting ad containers...");
  var arDivIds = ["AdSense", "watch7-sidebar-ads", "promotion-shelf", "live-chat-iframe"];
  var arDivClasses = [ "adDisplay", "annotation", "html5-endscreen", "iv-promo", "videoAdUiBottomBar", "ytp-endscreen-content", "ytp-cards-button", "ytp-cards-teaser" ];

  for (var i = 0; i < arDivIds.length; i++) {
    var oDiv = document.getElementById(arDivIds[i]);
    if (oDiv != null) {
      oDiv.style.visibility = "hidden!important";
      oDiv.style.display = "none!important";          
      oDiv.parentNode.removeChild(oDiv);
      console.log("YAD: Removed " + arDivIds[i] + " by ID");
    } else {
      console.log("YAD: Not found: " + arDivIds[i] + " by ID");
    }      
    sAdStyle = "#" + arDivIds[i] +  ((i==0)?" ":" , ") + sAdStyle;      
  }
  for (var i = 0; i < arDivClasses.length; i++) {
    var oDivs = document.getElementsByClassName(arDivClasses[i]);
    if (oDivs != null) {
      for (var j = 0; j < oDivs.length; j++) {
        oDivs[j].style.visibility = "hidden!important";
        oDivs[j].style.display = "none!important";          
        oDivs[j].parentNode.removeChild(oDivs[j]);
      }
    } else {
      console.log("YAD: Not found: " + oDivs[j] + " by ID");
    }
    sAdStyle = "*." + arDivClasses[i] +  " , " + sAdStyle;      
  }
  document.getElementsByTagName("head")[0].innerHTML = document.getElementsByTagName("head")[0].innerHTML + "\n<style>" + sAdStyle + "\n</style>";
}