Was struck by the sudden idea of Holmes being a psychic as an explanation for how he can make such crazy jumps in logic while investigating while still managing to be right.
My first thoughts for the specific powerset would be Psychometry (the ability to glean the past or future or the people connected to an object through touch) or Retro-Cognition (the ability to look into the past and clearly see past events).
I mean… It would make a lot more sense for the versions where the writers hide everything from the audience to “prove” how Crazy Smart Holmes is supposed to be.