I said leading up to TRoS that during the climax Anakin’s voice was probably gonna say something to Rey along the lines of “you’re the new chosen one now.” Everyone yelled at me and called me an idiot, but then that actually happened (“bring back the balance, Rey, as I once did”). That was probably my biggest “called it” moment.
I’ve had other accurate predictions over the years though. I had been saying since 2002 that Episode III would be called RotS. I had said that the new Disney films would only divide the fandom more than even the PT did. I said that TFA would be too predictable and then TLJ would be too different and then TRoS would be too fan servicey… Those are the biggest ones that come to mind.