I don’t think this rises to the example in the OP, but recently I was brought up short here on the boards.
We had a thread about what movie we would like to see made “warts and all”, about a public figure. I replied early on, but later intended to come back when I thought of something: I’d really like to see a movie about Red Sox great Ted Williams. He was the best hitter who ever played the game, Marine Corps fighter pilot, expert fisherman, basically the real-life John Wayne.
So I go back to the thread to add this and the very first thing I see is somebody had already posted the exact same idea. I felt like I had entered the Matrix because the poster said almost precisely what I was thinking, nearly word for word. I had a strange moment where I wondered if I had already written it and forgotten. Which is to say, great minds think alike. 