NOTE: An actor "playing the same character over and over" is often a comedian playing themselves, or simply someone with a lack of range. Either way, think long and hard about whether they truly qualify for this trope before adding them.
With Terry Gilliam directing and Michael Palin in a supporting role, Brazil featured expies of the rest of Monty Python, all seen here:
Sam (Jonathan Pryce), the naive, bemused protagonist => Graham Chapman
Spoor and Dowser (Bob Hoskins and Derrick O'Connor), the bumbling, comic-relief repairmen => Terry Jones and Eric Idle.
The character of Han, played by Sung Kang, in the Fast and Furious films is the same Han (also played by Kang) in the indie film Better Luck Tomorrow.
Norman Bates of Psycho and David Callaway in Hide and Seek have similar characteristics. They are protagonists of their films, they fight antagonists not shown to us, they found out that they themselves are the antagonists, and they have a Split Personality Takeover afterwards.
Like the Hager example, Jessica Priest from Spawn was created to replace Chapel, since it turned out his rights were tied to Rob Liefeld's Youngblood franchise.
Despite the use of many other characters from the comics, the Batman movies also have Expys for some characters:
Jack Napier is not only the Joker, but an Expy of Joe Chill, the mugger who killed Thomas and Martha Wayne.
Tim Burton didn't want to use Harvey Bullock in the 1989 Batman movie, he created the overweight, gruff, corrupt Lt. Eckhardt in the Batman movie.
In The Dark Knight, you have Officers Stephens and Ramirez, who are essentially Expys for Harvey Bullock and Renee Montoya, with the exception of, again, being that Ramirez is corrupt. Stevens on the other hand is Bullock right down to the toothpick chewing but his name was probably changed so the film wouldn't have two characters named Harvey.
Supposedly Ramirez was suppose to be Montoya but was changed because of the revelation of being a corrupt cop in The Dark Knight
John Cusack's Hitman with a Heart in War Inc. is an expy of his character in the earlier film Grosse Pointe Blank, and almost every other character in the new film has an equivalent in the previous one.
Alex from Home Alone 3 is the expy of Kevin from the previous two movies.
Star Wars, a lot of the characters from the Prequel Trilogy are Expies of characters from the Original Trilogy (Even if both characters are actually in the original trilogy):
Anakin Skywalker in episodes II and III is basically an Expy of his own son, even though he was also The Dragon in episodes IV, V, VI and even the end of III.
Qui-Gon Jin is The Obiwan TO Obi-Wan Kenobi, and is an expy of his own apprentice basically.
Darth Maul is obviously an Expy of Darth Vader in a The Dragon sort of way. Count Dooku is also an Expy of Darth Vader, but he's actually got more in common with The Emperor, and is more of a TheStarscream than a TheDragon. General Greivous is a bit closer to Vader; Darth Vader has trouble breathing, Grevious has a cough, and they're both cyborgs. Word Of God says the three were used in foreshadowing, each one being an element of Vader. Maul as The Dragon who enforces the emperor's will, Dooku as a fallen Jedi, and Grievous as a cyborg with breathing problems (though he only got them after Mace Windu used the Force to crush his chest).
In Gremlins 2: The New Batch, one Mogwai looks and acts very similarly to Stripe from Gremlins. The music sting, the way the camera zooms in and Gizmo's reaction all make it abuldantly clear to everyone including Gizmo that, for all intents and purposes, Stripe has been reborn. (Technically, both characters are brothers, as they both popped out of Gizmo's back after he got wet, and the New Stripe has black and white fur rather than blue and white, and after he becomes a gremlin, he has a reptilian frill rather than a Mohawk. But still undeniably an expy of Stripe.)
The villains in each of the direct sequels to Highlander — Katana in Highlander II: The Quickening, and Kane in Highlander III The Sorcerer — were pale imitations of the Kurgan, the memorable villain from the original. Kane even had the same deep, rough Dr. Claw voice as the Kurgan. Likewise, the villain from the TV series' pilot "The Gathering", Slan Quince, was also a Kurgan expy.
The Strangers with Candy film introduced Megawatti as an obvious expy for Orlando from the series because the actor who played him was too old to reprise the role.
In the Marx Brothers film each brother plays a character with a different name but the same personality as the character he played in the other films. As do some of the recurring supporting actors, most notably Margaret Dumont.
Edna is based on a real-life costume designer for Paramount, Edith Head.
Many say she was based on Linda Hunt's character Regina Krumm in Altman's 1994 film Pret-a-Porter. There is a serious resemblance, down to her size, her hairstyle, her black dress and her circular glasses!
If a place can be an expy, then the middle school that Violet attends is one for Corvallis High School in Corvallis, Oregon, where Brad Bird went to high school. This is down to them having the same mascot (the Spartans). However, since the high school building was torn down in 2005 and rebuilt, it's a little hard to see it now.
The Underminer is almost definitely based on Marvel's the Mole Man, an enemy of the Fantastic Four. Rumor has it that the film version of Fantastic Four was going to end in a similar way but it was changed when this movie came out.
Transformers II Revenge of the Fallen; In Transformers 1, of course, they couldn't have a giant robot turn into outdated '80s technology so they had an expy of Soundwave by taking one of Soundwave's tapes (Frenzy) and turning him into a CD player. In Revenge of the Fallen, they turn Soundwave himself into a satellite, and he sends another one of his tapes, Ravage, to Earth to spy on the humans. The whole Expy thing becomes a bit Meta, because Ravage spews a bunch of little metal balls which come together and form another character who is an expy of Movie 1's Frenzy!
Léon is Victor from Nikita. Same actor, and they even share an euphemism for their job, "cleaner". Luc Besson has said that they're basically cousins.
Winston Wolf, "the cleaner" from Pulp Fiction, is an Expy of the character played by Harvey Keitel in The Point of No Return — which was itself a remake of Nikita, thus tying all of these fellas together.
Victor◊ from Corpse Bride looks too much like grown-up Vincent◊, which was one of Tim Burton's first projects. The resemblance is even lampshaded in the film when Mr Everglot acidentally calls him Vincent.
The Filipino superhero Captain Barbell is quite similar to Captain Marvel, except that he has no lightning power and that his wimpy alter ego has to lift a barbell over his head to transform.
Sort of a type-casting example with Paul Bettany. He was in a biopic on Charles Darwin, and some reviews noted his previous role as Stephen Maturin in film Master and Commander who comes across as somewhat similar to Darwin in his time on the Beagle (intellectual naturalist on a ship, interacts with giant tortoises at one point).
George Sanders' The Falcon was a expy of George Sanders' The Saint. The Saint's author even brought suit against RKO over the issue.
The main characters in Buckaroo Banzai are all Expies of Doc Savage and his boys. Likewise, Buckaroo's unseen nemesis, Hanoi Xan, is an Expy of another pulp literary character, Fu Manchu.
In Dagon, Paul Marsh seems to be a deliberate homage to Jeffrey Combs.
William Gibson's recurring character Molly Millions was present in the origional short story "Johnny Mnemonic," but was replaced with a similar Action Girl named Jane in the film. The rumour is that this change was made because of some arguments about the film rights for Gibon's novel Neuromancer, in which Molly also appears.
In Return to Oz, Dorothy's new companions are not quite so different from her first companions from her first visit in Oz. Billina = Toto, Tik-Tok = the Tin Man, Jack = the Scarecrow, and the Gump = the Cowardly Lion. It verges into Suspiciously Similar Substitute territory, since these characters were also in The Marvelous Land of Oz and Ozma of Oz, which the movie was largely based on.
David Lynch wrote Mulholland Drive as a television pilot, and some believe a potential sequel to Twin Peaks. Lynch enthusiasts argue that the character of Betty/Diane in Mulholland Drive is an Expy of Audrey Horne on Twin Peaks.
Sgt. Stone seems to be a replacement for professional wrestler Sgt. Slaughter. Oddly, he's not the first Expy of him, with Beachhead having also filled the role. He also aligns with multiple "Lt. Stone" characters in Joe cartoons and comics.
In Superman's first clash with the Kryptonians in Man of Steel, Faora double-teams him along with an enormously tall and silent partner (Tor-An) who seems styled after Non from Superman II.
The fat, gravity manipulating deado from RIPD is similar to The Blob.