BlockTube

BlockTube gives you the control to customize your YouTube viewing experience. It allows you to block specific channels and videos that you don't wish to see or get recommended with.
The extension is lightweight and fast, integrated seamlessly and does not affect your browsing experience at all, to an extent that an unsuspecting user will never know it's there to begin with.

** The extension includes the following features

* Integrated context menus across YouTube for easy blocking
* Block videos by name
* Block channels by name
* Block comments from specific user or by content keywords
* Block/Allow videos with specific runtime
* Block YouTube Shorts
* Block YouTube Movies
* Block Explore page
* Block YouTube's auto generated playlists
* Hide watched videos from recommendations
* Remove "Video paused, continue watching?" popups

** For advanced users

* Regular Expressions are supported across all filter options
* Advanced Blocking: Extend the functionality on your own using a JavaScript function (https://github.com/amitbl/blocktube/wiki/Advanced-Blocking)
** WARNING ** DO NOT PASTE UNTRUSTED CODE YOU DO NOT UNDERSTAND, YOUR YOUTUBE ACCOUNT MAY BE AT RISK IF YOU DO SO

PRIVACY NOTICE:
I do not collect any information or data on you.
This extension does not contain analytics/tracking codes.
This extension does not make even a single request to a 3rd party server.
The only data being recorded is your configured options which are saved locally
only on your computer.

SOURCE CODE AND BUG TRACKING:
https://github.com/amitbl/blocktube

FIREFOX VERSION:
https://addons.mozilla.org/en-US/firefox/addon/blocktube/