There’s an anon with some weird random string of letters and numbers as a handle. Works on Bitcoin stuff, but maybe not Core. Consultant maybe? Can’t recall the handle. The characters “x”, “j” come to mind but I’m not sure.

Outside of Bitcoin, there was the author of the MimbleWimble paper who dropped it and then disappeared.

One of my favorite pre-Bitcoin anons was Why the Lucky Stiff, who wrote comics about the programming language Ruby.