I've lost count of how many times I've seen a good video or GIF on X (Twitter), meant to come back to it later, and found the post gone — deleted by the poster, or the account itself suspended. There's no warning, and no way to get it back once it's gone.
So I built myself a small page for it: paste the link to a public post, and it finds the video, GIF, or photos in it and hands you a downloadable copy. No app, no account, just a page.
If you've hit the same problem, X Video Downloader is free to use. It only works on posts that are still up and public — it can't recover anything that's already been deleted or is behind a private account, so it's worth grabbing a copy early if you think you'll want it later.