Here's what I got, and I'll say this is one of the most unsteady lists I've ever made because I'm not putting film against film but ranking two inconsistent bodies of work.
1. Harry Potter
While I wouldn't call my self a Potterhead and would rather fantasize or work in the story department of other Franchises on this list, Harry Potter is the one that's just one great film after another. I'm not saying this to re-open the argument over Fantastic Beasts. I love it, most of you don't. In terms of quality, the low points are the first half of Chamber of Secrets and... I don't know, maybe the pacing of Half-Blood Prince and Deathly Hallows Part 1.
2. The Living Dead
I am limiting this to the films actually directed by George A. Romero, so none of the remakes of Night of the Living Dead and Dawn of the Dead, none of the zombie spoofs like Return of the Living Dead and certainly none of the Italian films released as unauthorized sequels. George A. Romero's Dead series includes:
Night of the Living Dead (1968)
Dawn of the Dead (1978)
Day of the Dead (1985)
Land of the Dead (2005)
Diary of the Dead (2007)
Survival of the Dead (2009)
Night is Essential while Dawn is THE Epic Masterwork of zombie cinema. After that there's a drop in quality, but I've liked all of the films. While this may not appear to fit the cash cow label usually associated with a Franchise, the first two films were massive hits and the influence cannot be measured, though I would start with Shaun of the Dead.
3. James Bond
You can't argue with the longevity of the series, its ability to survive (and continue to make money) when the films aren't that good. In fact, it's the low points that make the good entries all the sweeter, and sometimes the lesser entries still deliver a great villain, Bond girl, stunt sequence or song
4. Star Wars
Nothing needs to be said here. The moment this topic was introduced the inclusion of Star Wars was never a question of 'if?", only a question of "where?" Now that George Lucas isn't the visionary behind every film and the films are venturing into the expanded universe, the decades of untapped story ideas are just beginning to see their way to the big screen. No other franchise has such a wealth of ideas to work from.
5. The Marx Brothers
Here's where the phrase "your generation" does not apply, and yet even while I was growing up I heard about the legendary Marx Brothers. Five of their thirteen feature films were selected by the American Film Institute as among the top 100 comedy films, with two of them (Duck Soup and A Night at the Opera) in the top twelve. They are widely considered by critics, scholars, and fans to be among the greatest and most influential comedians of the 20th century. I have to think for a long time, a new Marx Brothers film was viewed by the public with the same anticipation given to The Avengers today.
7. Marvel Cinematic Universe
This was a tough one to rank. The MCU has made a number of good films, but only a couple of Great ones. As a Franchise, they're very dependable, unlike the current state of Batman. However, I'm still more interested in The Caped Crusader as a character than any individual Marvel superhero, Probably because there have been Great ones spread out over decades, including Batman: The Animated Series and the recent Lego Batman. Compare that with a Lego Avengers which doesn't interest me in the least.
8. Mad Max
I don't now if there will ever be another Mad Max film, but George Miller has made four during three different decades and except for Thunderdome, each one has redefined action thrills and crazy/weird/cool.
9. The Muppets
From TV to Movies and back again, I am always interested in a new project starring The Muppets.
10. Sherlock Holmes (Basil Rathbone)
12. Road to...
Three Franchises from the past. Combined, they've only produced two Essential films, but they've been a pleasure to watch and re-watch. Zatoichi still has a number of the 26 film series I haven't seen yet, but it also boasts the 2003 reboot by Takeshi Kitano. The Road films of Bing Crosby and Bob Hope are the only Franchise that can't be rebooted, since their success depended on the two stars. However, many other comedy duos have tried, most notably in Spies Like Us, Ishtar and the animated film The Road to El Dorado.
13. Mission: Impossible
14. Broadway Melody - Series of 4 MGM musicals that all feature similar plot and cast.
15. The Fast and the Furious
17. Michael Shayne - 7 film series from 1940-1942 starring Lloyd Nolan
18. Miss Marple - 4 film series from 1961-1964 starring Margaret Rutherford
19. Star Trek
21. Lone Wolf and Cub
23. Resident Evil
24. Jurassic Park
26. Hercule Peroit (starring Peter Ustinov)
27. The Thin Man
28. Abbott and Costello Meet Universal Monsters