I want to add a couple of good ones I’ve found:
Jeff the Killer lost media: no one knows where the original Jeff The Killer image came from.
Mortis.com: old weird website
Also here’s a good website on various obscure computer/Internet related oddities: https://suricrasia.online/iceberg/
Every few years I look up if new evidence has been found and/or new suspects show up.
It’s always entertaining, but I’m guessing Satoshi Sakamoto is as smart as they come and we’ll never know who he/she is.