http://www.tubeoffline.com/
For the adult content sites like xhamster or xvideos, use this URL instead:
http://www.tubeoffline.com/download_adult_videos.php
They are still testing how to stream for DailyMotion, but they have a fantastic list of other websites they do support, including YouTube.
If you are a new-ish entrant into the Freeze-themed fantasy community like me, a lot of older and legacy videos are available on some of these sites. I spent one weekend systematically scanning each site they listed with the same set of keywords that pertains to my interests, and as a result I've increased my collection by quite a bite
![Very Happy :D](./images/smilies/icon_biggrin.gif)
Note: some of those sites listed may contain 'pirated' copies of content created by producers who are an active part of this community. Always think twice before downloading each video about who you might be harming.
Regards,
Erika