Once Watch: Hide Seen YouTube Videos by elanor.d

With a toggle, hide all the videos you've watched.

Storage is based in the plug in so it won't sync with your youtube watch history.

If you can get a list of videos you watched, you can import the history through .txt or .csv files

Import button: click "Import" in the popup, pick a .txt or .csv file. Each line can be any of:

Full URL: https://www.youtube.com/watch?v=dQw4w9WgXcQ
Short URL: https://youtu.be/dQw4w9WgXcQ
Shorts URL: https://www.youtube.com/shorts/VIDEO_ID
Bare 11-character video ID: dQw4w9WgXcQ