Greys out seen videos in the YouTube watch next sidebar, subscriptions page and elsewhere. Original: https://greasyfork.org/en/scripts/381500-youtube-grey-out-seen-videos
YouTube Grey-out Seen Videos (Fixed Sept 2025)
This script greys out videos you have already fully watched on YouTube.
Detects videos where the progress bar is 100% watched.
Greys out the thumbnail (opacity 0.5 by default).
Based on the original script: https://greasyfork.org/en/scripts/381500-youtube-grey-out-seen-videos
Notes
You can easily adjust the opacity value (thumbnail.style.opacity = "0.5") in the script if you prefer videos to appear lighter/darker.
This script only changes visuals — it doesn’t remove videos from the list.
