As you may know, searching formerly-Twitter for YouTube links sometimes gets results where there basically isn't any record of it anywhere else. I finally remembered my twitter.com login, so I can now used the loginwalled search feature. Test on npr video with >100M views:
> fail https://twitter.com/search?q=%22https%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3D4N1iwQxiHrs%22&src=typed_query
> works https://twitter.com/search?q=%22www.youtube.com%2Fwatch%3Fv%3D4N1iwQxiHrs%22&src=typed_query
> works not well https://twitter.com/search?q=4N1iwQxiHrs
> ( https://invidious.protokolla.fi/watch?v=4N1iwQxiHrs )

 >>/9042/
> got it a day or two ago
Next target could be this later on:
> https://endchan.org/.static/last50.html?b=pone&t=3148

 >>/9043/
For youtube-ixzONfzfxmE - nothing here:
> https://twitter.com/search?q=%22www.youtube.com%2Fwatch%3Fv%3DixzONfzfxmE%22&src=typed_query
> https://twitter.com/search?q=%22Check%20Yes%20Juliet%22%20%22MLP%22%20%22PMV%22&src=typed_query&f=top
> https://desuarchive.org/_/search/text/ixzONfzfxmE
> https://filmot.com/api/getvideos?key=md5paNgdbaeudounjp39&id=ixzONfzfxmE
> https://web.archive.org/web/*/https://i.ytimg.com/vi/ixzONfzfxmE/*
> https://web.archive.org/web/*/https://i1.ytimg.com/vi/ixzONfzfxmE/*
> https://web.archive.org/web/*/https://i2.ytimg.com/vi/ixzONfzfxmE/*
> https://web.archive.org/web/*/https://i3.ytimg.com/vi/ixzONfzfxmE/*
> https://web.archive.org/web/*/https://i4.ytimg.com/vi/ixzONfzfxmE/*
> https://archive.is/https://youtu.be/ixzONfzfxmE* and two other archive.is searches

Also gone (#15)
https://desuarchive.org/mlp/thread/40422488/#40440313