If you've had your YouTube account for a long time, you probably have lots of dead channels to which you're still subscribed since dubstep was cool. This tool will allow you to check your subscriptions for inactive (no uploads) channels, as per the filter you select.

Using this tool you can also rate (like/dislike/reset) a single video or all videos in a playlist.

Check out the code and implementation of this web app on GitLab.

*Disclaimer: Upon signing in Google will warn you that this app is unverified. However, no data is stored anywhere, besides your browser's local storage.

You can safely proceed and allow the app access to the account if you wish to use it by clicking "Advanced" and then "Go to application_domain (unsafe)".