Ask HN: Seeking lost gems of the web: what have you been unable to find again?

Hey everyone!

I'm curious about what interesting or important content have you searched on the internet for but just can't seem to find anymore? This could be an old video, a long-lost website, or even a piece of vital information that's disappeared. I'm eager to hear about the digital treasures you and we've lost! (can be a video, a website, a resources, or some important information).

Thank you for your time.