As for two different characters in the MCU, there aren't so many:
Aren't so many in significant roles that is. For an extensive list including all the unnamed background characters, see here. I've chosen to focus just on the characters with memorable roles who I can find pictures of.
Laura Haddock plays Peter Quill's mother, Meredith Quill (Guardians of ...
Severus Snape appears in all eight Harry Potter films, portrayed by British actor Alan Rickman. Rickman was Rowling's personal choice to portray the character. He had conversations with Rowling about his character and is one of the few Harry Potter actors that she spoke to prior to the completion of the book series about the future ...
The pattern here doesn't seem that unusual for the cast of a successful television show not to ever get another high-profile role; there are far more TV actors than TV roles to go around. In fact, many of the people on your list followed a typical pattern for television stars, which is to get one big break-out role, followed by scattered guest appearances in ...
Twice in fact.
From TNG Season 2 Episode 19, Manhunt (transcript here):
LWAXANA: Hello, computer? Is Commander Riker still on the Bridge?
COMPUTER: Negative. Riker is currently in holodeck three.
LWAXANA: Holodeck? Where is that?
COMPUTER: Follow the comm. panel lights. They will lead you there.
From TNG Season 5 Episode 20, Cost of Living (...
Patrick Stewart appeared in every episode; there's a discrepancy in how those two pages are counting.
Star Trek: The Next Generation aired 176 episodes. However two of those episodes, the premiere episode "Encounter at Farpoint" and the series finale "All Good Things...", were feature-length episodes. As originally broadcast, and as they're present on ...
In actuality, there's probably only about a dozen or so actors used for Stormtroopers (lots of actors are reused, like Jeremy Bulloch appearing in ESB as both Boba Fett and an unmasked Imperial Officer)
Most of the vast legions of Stormtroopers are created utilizing matte paintings.
A matte painting is a painted representation of a ...
Played the following enterprise/starfleet crewmembers:
In order she is portraying:
Enterprise-D Officer, TNG episode "Power Play"
Enterprise-D Officer, Star Trek: Generations
Defiant Weapons Officer, DS9 episode, "The Way of the Warrior"
She also played the following aliens:
In order these are:
Kiros, TNG: "Starship ...
There are 17 :
Griphook : Verne Troyer -> Wawrick Davis
Lavender Brown : Jennifer Smith -> Jessie Cave
Elphias Doge : Peter Cartwright -> David Ryall
Katie Bell : Emily Dale -> Georgina Leonidas
Tom The Innkeeper : Derek Deadman -> Jim Tavare
The Fat Lady : Elizabeth Spriggs -> Dawn French
Helena Ravenclaw : Nina Young -> Kelly Macdonald
He did try to act like a Klingon, but he also read his lines.
From Memory Alpha, with a citation to Star Trek: The Next Generation Companion, 2nd edition, p. 20:
Michael Dorn recalled his audition as follows: "I did not wear makeup, but I took on the psychological guise of a Klingon. I walked into Paramount in character. No jokes. No laughing with the ...
According to a BBC interview with LucasFilm's UK production executive Peter Beale, casting senior British actors in seeming title roles was instrumental in helping to get Fisher, Hamill and Ford work permits from the British Home Office which required letters of support from Equity, the actors union (without which the film couldn't have been made).
According to one of the special features in the Star Trek: Voyager disc set, Vaughn Armstrong has played 11 (!) unique Star Trek characters. He's been on all the live-action Trek series except the original. Looking at iMDb I found:
Lansor / Two of Nine
Mr. Spock (12, up to 15)
Leonard Nimoy, most famously
Zachary Quinto in the reboot continuity
Jacob Kogan played the young Spock in Star Trek (2009)
Spock appears as a baby in Star Trek V, although the name of the "actor" is unknown, so far as I know
Carl Steven played nine-year-old Spock in Star Trek III
Vadia Potenza played 13-year-old Spock in ...
While trying to add to Kyle's answer, I came across Randy Oglesby's entry on IMDB. The trivia blurb at the top of his page actually gives the answer: there are four actors who are tied for seven Trek roles each:
J.G. Hertzler (IMDB) (Memory Alpha)
Martok (and several variations thereof) - DS9
Vulcan Captain & Prophet - DS9
Roy Ritterhouse - DS9
Laas - ...
played the Vulcan security officer on Voyager and also a Klingon named T'Kar on DS9
He also played a human crewmember on the Enterprise-B, which fulfills OP's comment that he wished it was human, but he wasn't going to change the question.
Patricia Tallman has 10!
Human (played an Enterprise security officer in TNG "Power Play", the Defiant tactical officer in DS9 "The Way of the Warrior", and her face as appeared when playing Beverly Crusher in TNG, as body double for Gates McFadden; see here)
Ennis (played Nima, an Ennis female in the Gamma Quadrant in DS9 "Battle Lines")
Bajoran (played ...
Patrick Stewart recently released a (spoof) album of Cowboy and Western songs.
From the goodnewsnetwork website:
Billed in the video as “England’s premier cowboy singer,” Stewart
cracks a whip and dances in boots and chaps as he croons while selling
his collection of five tunes, like the theme from “...
You want an actor... or someone who has been in the largest amount of comic movies?
For a person... Stan Lee.
In X-Men (2000), Lee appears as a hotdog stand vendor on the beach when Senator Kelly emerges naked onshore after escaping from Magneto.
In Spider-Man (2002), he appeared during Spider-Man's first battle with the Green Goblin, pulling a ...
Simon Pegg was in the 2009 Star Trek as Montgomery Scott.
He was also in Star Wars: Episode VII - The Force Awakens as Unkar Plutt.
Deep Roy was in Star Wars: Episode VI – Return of the Jedi as Droopy McCool. He was also in the 2009 Star Trek as Keenser. For an added bonus he was Mr. Sin in the 1977 Doctor Who story arc The Talons of Weng-Chiang. Sci-...
Per Memory Alpha:
Patrick Stewart (Captain Jean-Luc Picard) and Jonathan Frakes
(Commander William T. Riker) are the only actors to appear in every
episode of the series.
That being said, Picard only had a single (pre-taped) appearance in TNG: Thine Own Self as the actor Patrick Stewart was doing a one Man "A Christmas Carol" show in London at the ...
According to this article in TrekToday, Michael Dorn (Lt. Worf) nearly left the show after the second season, stating that his makeup was causing damage to his skin:
Dorn said that he was very happy when his makeup time was reduced from
two and a half hours to a little over and (sic) hour, confessing that he
nearly left the show after the second ...
According to this article in Entertainment Weekly by Chris Lee, the initial rumor was floating around since May 2015 and the author of that same piece confronted him earlier in the year during an interview about the rumor and Daniel Craig’s response was:
“Why would I ever bother doing something like that?” Craig sputtered.
“F—ing hell! Pffft. Play an ...
Chris Evans has played seven comic-book characters in movies:
Johnny Storm/Human Torch in Fantastic Four (2005) and Rise of the Silver Surfer (2007).
Casey Jones in TMNT (2007).
Cpt. Jake Jensen in The Losers (2010).
Lucas Lee in Scott Pilgrim vs. the World (2010).
Steve Rogers/Captain America in The First Avenger (2011), The Avengers (2012), The Winter ...
Ryan Reynolds plays both Deadpool and Hannibal King from Blade: Trinity.
Also (half-jokingly), Stan Lee has played a character in many of the Marvel movies dating back to X-Men in 2000. Some samples are in the image below.
The official line is that he wanted to take "a break" from the show.
Michael Shanks was asked this question at San Diego Comic-Con International 2004.
When Michael was asked why he left the series in season 6 he joked,
"Because I hate Rob Cooper." After the laughter died down he followed
with the more serious response of, "I needed to take a break ...
Replicants in Blade Runner have a 4-year life span:
The "4-year lifespan" with regards to Harrison Ford refers to a long-running rumour / belief that Ford's character Deckard, a specialist in replicant termination, might actually be a replicant himself.
For more info, read here:
Blade Runner's Original Ending: Yes, ...
Credit where credit's due, Praxis' answer on Is this Beverly Crusher? gives Patricia Tallman, with ten:
TNG 5x15 "Power Play" - Human
TNG 5x17 "The Outcast" - J'naii (as a stunt double)
TNG 6x18 "Starship Mine" - Arkarian
TNG 6x25 "Timescape" - Alien pretending to be Romulan (we never get to see the alien's "true" form.)
DS9 1x13 "Battle Lines" - Ennis