Here are the “loose threads” – name-dropped cases we never hear the story of or the aspects of mysteries left unsolved – found in the Sherlock Holmes canon.

1. A Study in Scarlet
2. The Gloria Scott
   • What happened to Hudson?
3. The Musgrave Ritual
   • What happened to the maid?
   • The Tarleton murders
   • The case of Vamberry, the wine merchant
   • The adventure of the Russian woman
   • The singular affair of the aluminum crutch
   • Ricoletti of the club-foot and his abominable wife
4. The Speckled Band
   • What caused the untimely death of Helen Stoner alluded to as the reason Watson can now tell the story?
   • Mrs. Farintosh and the opal tiara
5. The Adventure of the Yellow Face
6. The Adventure of the Red Circle
   • The affair of Fairdale Hobbs
   • The Long Island Caves case
7. The Adventure of the Beryl Coronet
8. The Adventure of the Reigate Squires
   • the colossal schemes of Baron Maupertuis
9. The Second Stain
10. The Naval Treaty
11. The Crooked Man
12. The Twelve Orange Pips
    • The adventure of the Paradol Chamber
    • the Amateur Mendicant Society
    • the loss of the Sophy Anderson
    • the singular adventures of the Grice Patersons of Uffa
    • the Camberwell Poisoning Case
    • The Tankerville Club scandal, where Major Pendergast was accused of cheating at cards.
13. The Noble Bachelor
    • “…a parallel instance in Aberdeen…and Munich…”
    • “My last client of the sort was a king…The King of Scandinavia.”
    • The little problem of the Grosvenor Square Furniture Van
14. A Scandal in Bohemia
    • The Answorth Castle Business
    • The Darlington Substitution
    • A delicate matter for the reigning family of Holland
    • The case of the Atkinson Brothers of Trimcomalee
    • The Trepoff Murder in Odessa
15. The Valley of Fear
16. A Case of Identity
    • A delicate matter for the reigning family of Holland (either the same case as mentioned before or an ongoing matter)
    • “…parallel cases…in Andover in ’77, and there was something of the sort in The Hague last year.”
    • “Mrs. Etherege, whose husband you found so easy.”
    • “…a rather intricate matter which has been referred to me from Marseilles.”
    • The Dundas Separation Case
17. The Greek Interpreter
    • The Manor House case
18. The Sign of the Four
19. Silver Blaze
20. The Stockbroker’s Clerk
21. The Red-headed League
22. The Man With The Twisted Lip
23. The Engineer’s Thumb
    • Colonel Warburton’s madness
24. The Cardbboard Box
    • The bogus laundry affair.
25. The Hound of the Baskervilles
    • That little affair of the Vatican cameos
    • Wilson’s little case
    • The famous card scandal of the Nonpareil Club
    • The case of the unfortunate Mdme. Montpensier and the charge of murdering her step-daughter, Mlle. Carere