Review for Complete YouTube Saver by Firefox user 97ecdf
Rated 3 out of 5 stars
It's fantastic for downloading YouTube videos. Unfortunately, it doesn't work very well on other sites that use DASH streaming such as Vimeo. The use of open-source software like FFmpeg is also a nice touch with this extension versus some other video downloaders that claim to be free, yet they put QR codes on videos after muxing them unless you pay for the higher tiered version. Hopefully support for other websites can be added in the future.
To create your own collections, you must have a Mozilla Add-ons account.