The best extension ever made for YouTube. It's a shame that YouTube itself doesn't have this ability or anything like it at all.

Five stars ⭐⭐⭐⭐⭐

Update 1:
2 Stars ⭐⭐
FF 113.0.1 (64-Bit)
13.05.2023
Unfortunately no more checkboxes at the moment. Power button is missing. "Selection from to" not possible at the moment. From the usual five stars, unfortunately only 2 stars.

Update 2:
5 stars ⭐⭐⭐⭐⭐
FF 113.0.1 (64-Bit)
13.05.2023
After reinstallation, I only saw that the rights had to be reassigned.
Now the extension is working again.
Great web extension

Update 3:
2 stars ⭐⭐
Unfortunately, it has been no longer possible to select something in the subscription box (when grid view is selected) for a few days now (list view, however, works), since YouTube tinkered with its website (again).

Update 4:
5 stars ⭐⭐⭐⭐⭐
Super fast Dev 👍

FF 130.0.1 (64-Bit)
01.10..2024
3 stars ⭐⭐⭐
Only works in Watch Later List!

Update 4:
FF 130.0.1 (64-Bit)
02.10.2024
5 stars ⭐⭐⭐⭐⭐
Super fast Dev 👍

Nice effort. It only lacks the ability to add selection to specific playlist.

This addon is what I wanted. Thanks to the dev.
But this addon isn't perfect yet. First, the color of the interface being added does not match the background. Second, the placement of the interface makes the layout ugly.
I would like an option to hide the index number on all screens.
This review was generated by machine translation. I'm sorry if there is a part where the intention is difficult to convey.

Cette extension rajoute des fonctions supplémentaires sur YouTube:
● Sélectionnez la vidéo {0} à {1}
● Déplacez après ici (un ensemble de vidéo)

Please add an option to add things to a playlist (if you are in a playlist marking things)

Edit: I mean it would be great to select videos in one playlist and then be able to add them to a different one

Great for what it does. Missing a couple features I would like
1) Shift select/deselect to toggle a range. When on the liked videos playlist, I usually need to select a range of related recently watch videos and having to click each check is very time consuming.
2) Add to playlist. I use this for batch categorizing my liked songs. You can still do this by using add to queue button, and then youtube's own save queue to playlist feature.
3) De-duplication feature for playlist/queue, for anyone stupid enough to push save to playlist or add to queue twice. Youtube used to have a builtin de-dup button, but they got rid of it. Not really a feature I would expect from this, but one that wouldn't require much code change to do.