1. The "Red-Headed League": Initially, the story suggests that the "Red-Headed League" is a significant plot point, with its members seemingly involved in a bizarre scheme. This leads the reader to believe it might be relevant to the overall mystery. However, the league turns out to be a simple facade, designed to distract attention from the real scheme.
2. The "Missing" Irene Adler: The story opens with the assumption that Irene Adler is missing, and her disappearance is initially presented as a crucial element. However, it's later revealed she's not missing at all but rather using her disappearance as a tactic to gain an advantage.
3. The "Forged" Photograph: The idea that Irene Adler has a compromising photograph of the King of Bohemia is presented as a central element of the story. However, the photograph turns out to be a fake, created by Irene Adler to control the situation.
4. The "Stolen" Diamond: While not a true red herring, the story initially focuses on the theft of a valuable diamond. This element is later revealed to be secondary, with the real focus being on the blackmail plot involving the King of Bohemia.
5. The "Identity" of the Man in Black: The identity of the man in black who delivers the message from Irene Adler is initially ambiguous, adding to the mystery. However, the reader quickly learns he's simply a messenger, not a central figure in the plot.
Ultimately, the true red herring in "A Scandal in Bohemia" is the initial focus on the "missing" Irene Adler and the "compromising" photograph. Doyle skillfully uses these elements to create a sense of mystery and suspense, leading the reader to believe they are crucial to the story, while the real intrigue lies in Irene Adler's cunning and manipulative personality.