Plot Wheels
I showed a couple of examples, one old, one modern, on this post.
The old wheel was one of several supposedly used by "Perry Mason" writer Erle Stanley Gardner, and while the photo on the other post is an exercise in squinting, this website has the transcribed information from at least four wheels.
Here they are, though some - "servant", "heroine's maid" - are showing their age, so tweak and update as required.
I wouldn't suggest relying heavily on these - but at the same time, Gardner produced 119 or 82, the number varies, Perry Mason novels and according to Wikipedia at the time of his death was the best-selling American author of the 20th century.
So he may have been onto something after all... ;->
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A: Wheel Of Hostile Minor Characters Whose Function Is Making Complications For The Hero
These folks put obstacles in the hero's way and make it difficult for them to reach their goal.
1. Hick detective. 2. Attorney. 3. Newspaper reporter. 4. Detective. 5. Business rival. 6. Rival in love. 7. Father of heroine. 8. Blackmailer. 9. Gossip. 10. Meddlesome friend. 11. Suspicious servant. 12. Hostile dog. 13. Spy. 14. Incidental crook. 15. Hotel detective. 16. Thickheaded police.
B: Wheel Of Complicating Circumstances
1. Hero is betrayed to villain by spies. 2. Every move the hero makes takes him from the frying pan and puts him into the fire. 3. Heroine's maid is a spy. 4. Father of heroine is hostile to the hero. 5. Detective believes the hero is guilty and tries to arrest him/her at a critical time. 6. Hero commits an incidental crime. For example, he/she is caught speeding and is arrested. 7. Witness mistakes hero for villain. 8. Hero violates the law and is sought. 9. Heroine's mind is poisoned against the hero. 10. Some character is not as represented. 11. Rival in love tries to discredit the hero. 12. Zeal of hick cop upsets plans.
C: Wheel of Blind Trails By Which The Hero Is Misled or Confused
1. Witness lies. 2. A document is forged. 3. A witness is planted. 4. A client conceals something. 5. A client misrepresents something. 6. A friend pretends to betray the hero. 7. The villains assistant pretends to betray the hero. 8. A vital witness refuses to talk. 9. False confessions. 10. Genuine mistakes. 11. A witness takes flight. 12. A witness is kidnapped. 13. A witness commits suicide. 14. A witness sells out. 15. Planted clues. 16. Impossible statements.
D. Wheel of Solutions
How the hero surmounts the obstacles thrown in his way.
1. Gets villain to betray himself through greed. 2. Gets the villain to, of his own free will, plant additional evidence. 3. Plants fake evidence to confuse the villain. 4. Fakes circumstances so the villain will think he / she has been discovered. 5. Tricks the hero's accomplice into confessing. 6. Villain is hoist by his / her own petard. 7. Villain killed while he / she is trying to frame someone. 8. Gets villain to overreach himself/herself. 9. Meets trickery with horse-sense. 10. Squashes obstacles by sheer courage. 11. Turns villains against each other. 12. Traps [tricks?] villain into betraying a hiding place. Hero either a) creates a fake fire, or b) gives him / her something else to conceal, or c) makes it necessary for the villain to flee (and so must take something out of the hiding place).
