Dead Man's Gun: While smarter than most examples of the trope. Leo in "The Imposter" manages to go through various successes in a job as marshal he has no experience for with a few clumsy shots, speaking the honest truth to people at times, and occasionally moving at just the right moment to avoid being shot.
Played with in Firefly. While most fools are depicted as happy and childlike, Jayne Cobb, easily the dumbest member of the cast (despite his talents for interrogation) is also grouchy and generally unhappy.
Maxwell Smart in Get Smart is the most successful field agent available to CONTROL. This does not however, mean he's the brightest or most competent.
Sgt. Schultz from Hogan's Heroes. Played with in that he was actually on the prisoner's side, or at least genially corrupt, from the very beginning.
Referenced directly in the Librarians episode "And the Fables of Doom". Magic causes the team to take on the characteristics of various fairytale archetypes, with Ezekiel becoming the Fool. It's noted that this makes him the only one who's safe from being killed off by the narrative, since characters of this type are supernaturally lucky.
