Deadly Hands of Kung Fu has the biggest set of famous fictional heroes, antiheroes, and villains in one crossover action-flick, predating the Marvel Cinematic Universe.
Every opponent Bruce Lee faces are from book-based-films of diverse genres: Count Dracula, a gothic-monster novel character; Emmanuelle, an erotic-fantasy novel character; James Bond 007, an action-spy novel character; The Exorcist, a supernatural-horror novel character; The Godfather, a mafia crime-drama novel character; and Zatoichi, an edo-period ronin novel character. Man with No Name is the only opponent who doesn't originate from any novel, but rather from a theatrical motion-picture.
The three fictional allies of Bruce Lee are from different forms of entertainment media: Kwai Chang Caine being a character from a series; One-Armed Swordsman being a character from a movie; and Popeye the Sailor Man being a character from a cartoonist.