Is there something like archive.is but for YouTube Videos?

Using the wayback machine can work if you have the exact video link, but it's not guaranteed that they'll have it

You can occasionally find a torrent out there of some channels entire video log

Other than that, no

If you come across a video that you really want to save, just use ytdlp to download it

I actually found several of the deleted YouTube videos on archive.org, but it was pretty hit or miss and was mostly the older ones.

For personal copies of videos I want to keep incase of deletion, I generally look to yt-dlp.