I actually purchased a copy of '4K Video Downloader' for this very purpose, and previously used Internet Download Manager for many years (I still use IDM as a backup as 4k sometimes can't download videos with particular settings). I was able to save a few pulled videos this way, and have an extensive collection I can look back on. It is a kick to see postage-stamp sized videos of memes I was watching in the mid 2000's. I don't keep everything I download, but I download everything I watch.