Practically every Mitchell and Webb production includes Olivia Colman - one of whose key early roles was Sophie from Peep Show, which also stars David Mitchell and Robert Webb - and James Bachman.
There is a lot of osmosis between Full House, Step by Step, and Family Matters; they had the same producers and the same lead vocalist for their theme songs.
Dan Schneider in the Nick Verse (Nickelodeon shows iCarly, Victorious, Drake & Josh and Zoey 101) has certain actors having 3 or 4 different characters in the same shared universe. The main force behind this is that Dan reuses favoured actors as well as finding his future lead stars by casting them in guest or less than starring roles whilst they are younger. For example, Miranda Cosgrove had iCarly built around her through her work as Megan on Drake & Josh, with Nathan Kress being recruited for the show because of a one-shot guest character named Toplin. Jennette McCurdy's character Sam is based on a one episode character she played in Zoey 101. Victoria Justice was in Zoey 101 and iCarly before Victorious, which was built around her when Dan identified her as a future star years earlier when she was on Zoey 101. Also Taran Killam seems to pop up in his works somewhere as well.
During the 1970s, Mexican TV producer Roberto Gomez Bolaños (AKA: "Chespirito") used the same pool of actors on all of his shows, usually playing similar characters. This was particularly noticeable on El Chapulín Colorado, which only had one regular character (El Chapulin, played by Bolaños himself) since any other characters in the show where played by actors from his other hit show, El Chavo del ocho (where they played regular characters.) They consisted of some combination of himself, Carlos Villagrán, Ramón Valdez, Florinda Meza, María Antonieta de las Nieves, Edgar Vivar, Ruben Aguirre, and (occasionally) his younger brother Horacio Gomez Bolaños.
A Disney Channel Original Movie made these days will likely feature one, or more, or several stars from the channel's original series, and maybe similar directors or writers.
Likewise, many of the Disney Channel's stars from a six or seven year period started as special guests in the period previous to it. Shows premiering around 2010 or 2011 (Shake it Up, A.N.T. Farm, Good Luck Charlie) largely star actors and actresses who had a guest role on Hannah Montana and/or Wizards of Waverly Place beforehand.
Miley Cyrus seems to the exception. Aside from a non-speaking, blink-and-you'll-miss-it cameo (as a background dancer!) in High School Musical 2, she has never appeared in a Disney Channel Original Movie.
The recurring guest star posse used to only really apply to Disney Channel's movies with many actors such as Ryan Merrimaan appearing in multiple ones some of the show actors would as well, but the shows mostly kept to themselves with actors being confirmed to there own shows. Eventually more and more actors from the series started appearing in the movies, and only very recently has this happened with actors appearing on other shows. Selena Gomez may be one of the first example of this with her appearance on The Suite Life of Zack & Cody and later Hannah Montana, and eventually landing Wizards of Waverly Place.
Rob Thomas (of Veronica Mars fame) works with Diane Ruggiero, Dan Etheridge and John Enbom on a regular basis, and actors who appeared in one series tend to pop up in his subsequent shows, even for a one-off appearance, Ryan Hansen being the most obvious one, but Adam Scott, Martin Starr, Kristen Bell, Alona Tal, Jason Dohring, Enrico Colantoni, Jane Lynch, Steve Guttenberg and many more have appeared in two or more Rob Thomas shows.
Clive Doig's puzzle-based Edutainment shows for The BBC generally featured one or more of Janet Ellis, Sylvester McCoy, Mark Speight, Julia Binstead, Phillip Fox and Wilf Lunn.
With any Syfy show, expect to see several guest appearances by actors from other Syfy shows. Sanctuary and Warehouse 13 are the best examples, with the former featuring several Stargate alumni, and the latter featuring guest appearances from almost every other Syfy show that was currently airing at the time.
American Horror Story changes its cast and plot every season, but each one to date (including the forthcoming Freak Show) has had Jessica Lange, Sarah Paulson, Frances Conroy and Evan Peters in common.
Chuck Barris always used Johnny Jacobs as an announcer from about the early 1970s onward. After Jacobs' death, he was replaced by Tony McClay.
Bob Stewart: Bill Cullen will always be involved in some way, either as a host or celebrity guest; if not him, then either Dick Clark, Jack Clark, or Geoff Edwards. Bob Cobert was usually the Theme Tune composer. If there are other celebrities involved, expect Markie Post, Joanne Worley, Nipsey Russell, Henry Polic II, Teresa Ganzel, Ilene Graff, Nathan Cook, etc. They were even termed by the Game Show Pilot Light as the Bob Stewart Repertory Company.
Mark Goodson: Nearly every show, at least from the 1970s onward, had either Gene Wood or Johnny Olson as an announcer, and either Edd Kalehoff or another member of Score Productions composing the Theme Tune.
Merrill Heatter-Bob Quigley: Always announced by Kenny Williams, except Temptation (no relation to the Sale of the Century knockoff of the 2000s) and The Magnificent Marble Machine. Mort Garson or Stan Worth composes the music, and quite often the host will be Peter Marshall, Wink Martindale, Alex Trebek, or Art James.
Jack Barry-Dan Enright: Theme Tune usually composed by Hal Hidey, with either Charlie O'Donnell, Johnny Jacobs, or Jay Stewart announcing. John C. Mula usually designed the sets. Richard S. Kline always served as director (until he and several other B&E staffers defected to form Kline & Friends, which produced Win, Lose or Draw and the 1990-91 version of The Joker's Wild, among others).
You'd be hard pressed to see an improv showcase on television that doesn't include Ryan Stiles, Colin Mochrie, Wayne Brady, Greg Proops, Brad Sherwood, Jeff Davis, and/or Kathy Kinney. In fact, because of their association with a certain popular improv series, the public has affectionally dubbed them, "The Whose Crew."
Drew Carey, in particular, used a lot of these performers in many of his projects, both improv and scripted. In the case of the former, all of the above-mentioned performers (and more) have appeared on Improvaganza and Green Screen Show; for the latter, Ryan Stiles and Kathy Kinney were co-stars on The Drew Carey Show, Colin Mochrie was a semi-regular, while Brad Sherwood, Wayne Brady, Greg Proops, and others appeared specifically in the live episodes.
And a few years after Drew took over on The Price Is Right, Drew even tapped Sherwood and Davis as substitute announcers after Rich Fields left the show (the show ultimately went with George Gray). In turn, he also had Fields as announcer on Drew Carey's Improv-A-Ganza. And Wayne Brady's announcer on Let's Make a Deal, Jonathan Mangum, has popped up on many of the newer shows, including the new version of Whose Line.
Kenny Leon has directed some predominantly-African-American TV adaptations of various plays with Craig Zadan and Neil Meron as producers. Queen Latifah often becomes part of the cast, and also appeared in some movies Zadan and Meron produced under different directors.
The CW is basically a network-wide example. Examples include:
Stephen Amell's cousin Robbie was previously the main star in the short-lived The Tomorrow People before recurring as Firestorm in The Flash.
Legends of Tomorrow, which consists of actors playing characters from Arrow and The Flash. When Season 2 started, they brought in Maisie Richardson-Sellers from The Originals to play Vixen. Season 3 added Courtney Ford, who actually had to briefly juggle between starring in Supernatural seasons 13 and 14 (in which she recurred) and Legends seasons 3 and 4.
Star-Crossed stars Matt Lanter from 90210 and Creator/Malese ow from The Vampire Diaries as well co-star Susan Walters in a recurring role. Jow, Walters and regular Greg Finlay would let book roles on The Flash.
Alexander Calvert, who recurs in Arrow season 4, later appears as a main character in Supernatural from season 13 onward.
Ultra Series: In the early series (Ultra Q, Ultraman, and Ultraseven), Eiji Tsuburaya used pretty much the exact same selection of writers, directors, and SFX artists, notably head writer Tetsuo Kinjo, his son Hajime Tsuburaya, and monster artist Toru "Tohl" Narita. A few actors were also transferred between series, like Hiroko Sakurai and Sandayu Dokumamushi. Additionally, many of these people had worked with Tsuburaya on his Toho movies.
David Simon has multiple actors that he uses and reuses over again. The list of actors he's used in two or more shows is too long to list. Even limiting the list to actors appearing in 3 or more shows, it still includes Maria Broom, Reg E. Cathay, Anwan Glover, Michael Kostroff, Clayton Le Bouef, Clarke Peters, James Ransone, Corey Parker Robinson, Lee Tergesen, and Jim True-Frost.
Several actors have not just guested, but starred in more than one of Bambu Producciones' shows. A nonexclusive list includes: Paula Echevarría, Javier Rey, José Sacristán, Manuela Velles, Eloy Azorín, Llorenç González, Daniel Lundh, Yon González, and Amaia Salamanca.
Doctor Who and multiple shows from British production company Kudos - Broadchurch alone features 21 (25 if you include Big Finish audio stories based on Who) actors who’ve also appeared in Who, including three past or future Doctors and one companion.
While Chuck Lorre's shows don't tend to cast actors in main roles more than once, several actors have had recurring/guest roles on several of his shows. Among them are Melissa Tang (guest on The Big Bang Theory, Young Sheldon, and B Positive; recurring on The Kominsky Method and Mom), Brian Thomas Smith (guest on Two and a Half Men, recurring on The Big Bang Theory and United States of Al), Sara Rue (recurring on Two and a Half Men, The Big Bang Theory, and Mom; main role on B Positive), Jane Seymour (guest on Dharma & Greg, recurring on The Kominsky Method and B Positive.), John Ross Bowie (recurring on The Big Bang Theory and United States of Al), D.B. Sweeney (recurring on Two and a Half Men and B Positive), Jason Kravits (guest on Young Sheldon, The Big Bang Theory, and The Kominsky Method; recurring on B Positive), Missi Pyle (recurring on Two and a Half Men, Mom and Disjointed; guest on Bob Hearts Abishola), Elizabeth Sung (guest on Mike & Molly, Disjointed, and The Kominsky Method), Ryan Cartwright (recurring on Mom and B Positive; guest on The Big Bang Theory and Bob Hearts Abishola), and Allison Janney (guest on Two and a Half Men and The Kominsky Method; main role on Mom).
A particularly interesting example of this is Vernee Watson, who had recurring or guest appearances on Grace Under Fire, Two and a Half Men, The Big Bang Theory, Mike & Molly, and Young Sheldon, as well as a main role on Bob Hearts Abishola. Her appearances are particularly notable in that she plays a nurse in nearly all of them.
Billy Gardell is a rare example of an actor who does have a main role in multiple Chuck Lorre series, as he starred in both Mike & Molly and Bob Hearts Abishola in addition to playing a recurring role on Young Sheldon.
Emily Osment has had an increased presence in various Lorre productions, starting from a special guest role in one episode of Two And A Half Men as Angus' girlfriend Ashley, a recurring role as Jodi in season 3 of Mom, a role in The Kominsky Method as Theresa, and more recently, a role as Mandy McAllister in Young Sheldon.
The Hexer: Michał Żebrowski (Geralt) and Zbigniew Zamachowski (Dandelion) played prior together in the film adaptation of With Fire and Sword. More, their roles were also those of the True Companions.
The Lord of the Rings: The Rings of Power has involved in its production many of the big names that were behind the creation of The Lord of the Rings and The Hobbit. New Line Cinema is involved in the production of the show just as it was with the trilogies, Howard Shore produced the intro, Jed Brophy, who portrayed Orc Sharku and other random orcs in the Lord of the Rings and the Dwarf Nori in The Hobbit, plays an orc in the show too, Creator/WETA in the CGI department, and John Howe serves as conceptual designer chief like he did in the movies. Amazon almost had Peter Jackson involved too.
as the Bob Stewart Repertory Company.
