...and Bunbee in Yes! Precure 5GOGO. Probably also Mika—her face isn't visible, but there's a camera on the table next to her which has no purpose in the scene unless it's there to identify her.
The JPN Pokémon openings regularly change to effect new captures/releases, and much speculation is made on upcoming captures based on empty space in the titles.
Hanyuu in Higurashi: When They Cry, promoted directly from The Voice to one of the heros. Ironically, Keiichi too. Despite the fact he was arguably the most important character in season one, he didn't appear in the opening to that season.
Sgt. Frog has done this to numerous characters, the first being The Ghost who was added into the first season credits about halfway through. The trope has also been played in reverse as characters have also been removed from the opening credits.
When the YuYu Hakusho opening changed at some point in the Chapter Black Saga (it only does in the Three Kings Saga of the English version), it included characters like Kaito, Yana and Kido, as well as arc antagonists Sensui and Itsuki, and the third opening included Yomi, Mukuro and six former opponents from the Dark Tournament. The lineup at the end of the second opening expanded to include Kaito, Yana and Kido, added Shizuru (who was in the first opening, but not at the lineup at the end). In an inversion, Atsuko, who lacked the few scenes she had in the late manga in the anime adaptation, was removed in the second version of the lineup at the end.
One Piece often mentions characters long before they appear or play a truly significant role, and leaves them out of the openings until they do. Blackbeard first appears in the sixth opening, despite having appeared in the series and being mentioned several times before that. Dragon, despite appearing in Loguetown and being mentioned on some occasions after that, became important enough to get in the opening after momentarily appearing in the Post-Enies Lobby arc and being revealed as Luffy's father]. He also appeared briefly in the second opening, which began running during the Loguetown arc.
In the 4Kids dub, the "One Piece Rap" has different lyrics that include Usopp, Sanji, and Chopper when they joined the crew. It's unknown if they ever did record a version that added Robin since she joined near the end of that dub's lifetime.
In Fang of the Sun Dougram, by the time George and Hackle finally get their places in the opening credits (with George replacing Festa), they're already permanent and indispensable team members.
After Kamina's death in Tengen Toppa Gurren Lagann, Nia replaces him in the second title sequence. They each get their own place in the third.
Ironically, in the same episode, Thymilph is added along with the rest of the Quirky Mini Boss Squad, despite dying in the previous episode.
In Digimon Adventure, the dub's intro and outro footage were recut about halfway through the season in order to account for Kari, Gatomon, and the higher-level partner Digimon.
In Puella Magi Madoka Magica there's an interesting case of this. All five of the girls show up at various points in the OP, but the final shot only shows Madoka, Mami, and Sayaka. After episode ten, they are joined by Homura and Kyouko.
After Yamada is introduced in the seventh episode of WORKING!!, she is quickly added to the end credits of the episode, and then also included in the opening of the following episode.
In Galaxy Quest, the Show Within a Show's original cast is accompanied on their for-real adventures by a Plucky Comic Relief called Guy, who fears he's a Red Shirt because he has no last name. (It helps that he even played a one-shot character on the show, of the sort that always gets vaped.) He has one, but it's not mentioned until the end of the movie, where the credits to the revived Show Within a Show read: "And introducing Guy Fleegman as Security Chief 'Roc' Ingersol". The Thermian female who falls in love with Fred also appears in these credits: "Jane Doe as Laliari."
It's even funnier in the Spanish translation. Her name is given as "Fulana de Tal", which basically translates as "So-and-so Whatsis."
The Harry Potter films don't have "opening" titles, as they save all the credits until the end. However, Bonnie Wright (Ginny Weasley) has appeared in every film since the first one, albeit with just a Mandatory Line in two of them, but only got to be listed in the main titles after she got a bigger role in the sixth movie.
The first instance came when Jaleel White (as Steve Urkel) was added at the beginning of Season 2. Urkel already had began figuring heavily into the plots late in the first season, and given his instant popularity, it naturally made sense to promote him.
Shawn Harrison as resident idiot Waldo Faldo, starting with Season 4. This was another case of rewarding the popularity of a breakout character — the bully's sidekick to dumb-but-loveable best friend — by adding him to the opening credits.
Michelle Thomas as Myra Monkhaus, starting with the sixth season. Myra also had gained enough popularity to earn Thomas her spot.
Although the opening theme was discarded by Season 8, Orlando Brown (as 3J) was added in the listing of names during the opening scene.
Happy Days: The original opening credits (for the early 1974 episodes) billed four actors: Ron Howard, Marion Ross, Anson Williams and Tom Bosley. Henry Winkler (as the Fonz) was not in the original opening credits for the earliest episodes. The following changes occurred during subsequent seasons:
Winkler and Don Most (as Ralph) were added in Season 2, both after Ross and Williams, who were billed second and third, respectively.
Starting with Season 3, Erin Moran (as Richie's younger sister, Joanie) is added to the credits, increasing the number of billed characters to seven.
Scott Baio — who becomes a recurring, then semi-regular, then full-time cast member in the fifth season — is not added to the opening credits until Season 7, even though he is seen in the opening credit montage.
Lynda Goodfriend, who had played Richie's girlfriend, Mary Beth, as early as the fifth season, is not given an opening credit until Season 8!
Season 10 saw the additions of Cathy Silvers (as Jenny Piccolo) and Ted McGinley (as Roger Phillips); both had appeared on the show as early as Season 8 and had appeared in the final group shot (along with Winkler, Moran, Baio and Williams) at the end of the opening theme. Billy Warlock and Crystal Bernard are never given their own billing, even though both were semi-regulars.
Mary Kate and Ashley Olsen — arguably, the best known actresses from the show — were not given their own billing in the opening credits during the original first-run ABC series; they were not permanently added until Season 2. (Their credits were added in syndicated episodes, however.)
Lori Loughlin (as Rebecca Donaldson, Jesse's soon-to-be bride) is added for Season 3, after being a recurring character turned regular during the second season.
Andrea Barber (as annoying best friend Kimberly "Kimmy" Gibbler) is added in Season 5; she had been a recurring character way back in the first season, as this was a way to give Barber more screen time.
Dylan and Blake Tuomy-Wilhoit, who played twins Alex and Nicky Katsopolis, were added in Season 8, after being featured more and more during Season 7.
The Hogan Family: Although Edie McClurg is given her own credit when she begins appearing in the second season, she does not get her own credit clip – stock footage of her greeting the Hogans with tea and other refreshments – until Season 3.
Little House on the Prairie: When the series began in 1974, only the actors that played the Ingalls family members – Michael Landon, Karen Grassle, Melissa Sue Anderson, Melissa Gilbert, and twins Sidney and Robin Greenbush – were shown on camera (Charles and Caroline in the wagon, and the girls running down the hillside). Most of the supporting characters were listed under "The Town." However, there were several changes through the years:
Starting in Season 3, Alison Arngrim (as Nellie Olesen) and Jonathan Gilbert (as Willie Olesen) are moved to "The Town" listing whenever their characters appear. Previously, they were listed only in the closing credits.
When the series became Little House: A New Beginning in 1982, Dean Butler, Katherine MacGregor, Richard Bull and Victor French were moved from "The Town" (whenever they appeared) to the opening credits, and were billed that way – along with series lead Melissa Gilbert – throughout the season.
The rest of the main cast were billed in the opening credits of the movies.
After having the exact same opening titles for 8 seasons (aside from adding Robert Patrick in season 8), The X-Files updated them for the 9th season, since the original titles looked outdated due to cast changes, cast aging, and new developments in the Myth Arc. This was when Assistant Director Walter Skinner, who was introduced back in the latter half of the 1st season, finally got clips and an actor credit in the opening titles.
David Boreanaz, James Marsters, Emma Caulfield and Seth Green in Buffy. And, because it appears that Mutant Enemy has a rule that if you're going to do something, make it angsty, Amber Benson was also promoted in her third season - for one episode, then she was killed off (in a deliberate subversion of this trope). Marc Blucas was a bogus example, as he was marked for promotion from the moment he entered the show.
Inversion averted: Joss Whedon wanted Jesse to be in the opening credits to the first episode, despite being killed off in the same (or second, if it's split into a two-parter). They didn't have the money to do two versions of opening credits.
Across the Buffy Verse in Angel, Andy Hallett took two and a half seasons to get promoted (it finally happening partway into Season Four), and Mercedes McNab was promoted for the final six episodes only and she rarely ventured out of Garfunkel territory. (Though it was intentional, as well as lampshaded). Another Angel example: Nearly everyone added to the opening credits [except David Boreanaz, Charisma Carpenter and Glenn Quinn, since they starred in the Pilot] guest starred in at least one episode before they were promoted. A common theme included the character appearing at the end of the previous season and returning in the fall as a new star.
Parodied in the episode "Superstar" where Danny Strong (Jonathan) is not only added to the opening but prominently featured as the main attraction. It turned out that he summoned a demon who altered reality to make him the most successful and popular man on earth. While the spell was active, he was a better slayer than Buffy, smarter than Willow, more knowledgeable on demons than Giles and had a strong career as both a rock star and an underwear model. He was even credited for inventing the internet.
Alyson Hannigan gets a promotion along the credits themselves. When Anthony Stewart Head stepped down to Special Guest Star Recurring Alyson moved from third in the credits to the much more exciting final credit with the super neat "And/As" combo.
Of course, this was a cash in on her rising fame.
Michelle Trachtenberg (as Dawn), although she is only really a partial example. Trachtenberg was only a guest star for one episode, because her first appearance was supposed to be a surprise (and because Emma Caulfield had just been promoted in that episode).
Kelsey Grammer was originally hired to play Fraiser Crane for seven episodes of Cheers. Not only did he stay on and get promoted to the opening titles, his character was given a hugely successful spinoff. Bebe Neuwirth originally only had a three-minute guest spot in the middle of season four; she wound up getting added to the opening titles, winning two supporting actress Emmys for the show and making frequent appearances on Frasier over the ensuing decade.
John Ratzenberger (Cliff Clavin) was added to the credits beginning in the second season.
Speaking of Frasier, Dan Butler got his name into the Opening Credits in seasons four through six, but, ironically, he appeared in fewer episodes, and after that his character for a long while vanished.
Near the end of her first run on Law & Order, Carolyn Mccormick as Dr. Elizabeth Olivet managed to get mention in the opening credits, however, a photo of her in character was not created, as is L&O tradition.
B. D. Wong (Huang) and Tamara Tunie (Warner) on Law & Order: SVU. In Season 15, Raúl Esparza (Barba) got added.
Michael Emerson was contracted for just a few episodes of LOST in the second season as "Henry Gale" (Ben). He was so loved/loved to be hated that he became a cast member in the third season, where he served as the Big Bad.
Ana-Lucia appeared first as an guest star in season one, albeit in flashbacks.
This one doesn't really count, as at that point Michelle Rodriguez had pretty much been cast for the second season, and the guest appearance was only an early introduction.
Likewise, Henry Ian Cusack (Desmond) was a guest star before being a regular.
Little known fact: Eko was a guest star for a couple of episodes before quietly being promoted to regular.
Somewhat confusing variation: five of the main characters were billed incorrectly as guest stars in the publicity for the season, despite being credited as main cast:
In season 3, this hit Nikki & Paulo. While they were planned to be main characters with a fairly involved arc, they turned out to be widely hated and not important in the least, and were quickly killed off. The decision to do that was made before their introduction even aired, thus causing the mix-up.
In season 4, Miles, Daniel, and Charlotte were not in the promo pictures and were said to be guest stars in press releases. The reason for this is that they were meant to be guest stars, but as they were filming their first episode the producers liked all three and signed them up...sadly, too late to change the press releases or promo pics. By season 5 all three were in the promo pics, but Charlotte was still a guest star in publicity due to her character dying just five episodes in.
Nestor Carbonell (Richard) appeared in several season 3, 4 and 5 episodes and got a semi-centric episode in season 5 before becoming a main cast member for season 6 (complete with a completely centric episode).
Jeff Fahey actually turned down the same regular contract offered to the other actors playing members of the science team (Jeremy Davies, Rebecca Mader, and Ken Leung) but has later became a regular for season 6.
After guest starring on the series for years, Sam Anderson, L. Scott Caldwell, Francois Chau, Fionnula Flanagan, John Terry, and Sonya Walger finally got their names in the main cast credits...for the final episode. Said episode also added back all of the former regulars appearing, making it so the episode credits an amazing twenty-eight people as starring.
For the first season of Gilligan's Island, the theme song referred to Russell Johnson (the Professor) and Dawn Wells (Mary Ann) as "and the rest." Star Bob Denver personally demanded that those cast members be given full credits in the succeeding seasons.
The way he did it though was nothing short of brilliance. As the star getting top billing, his name was required to be in the song. His initial request for them to be included was rejected. So he simply demanded his credit be at the end of the tune, forcing them to put the other two in before his. The network relented and added them, rather than be forced to completely change the song.
And Denver never told Johnson and Wells that he was the one who got their credits included. They both found out what Denver had done for them years later from somebody else.
This used to be how everyone except the original main cast made it to the title credits in Degrassi The Next Generation, being introduced as minor characters in the previous season. This changed in the tenth season, when characters began coming from essentially out of the blue.
Janel Moloney and Stockard Channing on The West Wing, both appearing as regular guest stars in the first season. Moloney joined the main cast in the second season, Channing in the third.
Joshua Malina as Will Bailey, first appeared as a guest character in a few episodes in Season 4 before a speedy Promotion to Opening Titles.
Also happened to Jimmy Smits and Alan Alda as Presidential candidates Matt Santos and Arnold Vinick later in the show, in Season 6. Smits appeared in the opening credits in his first episode; Alda was a Special Guest Star in his first, and in the credits from his second onward.
Averted with Mary-Louise Parker as Amy Gardner, who Sorkin was interested in promoting to main cast but ultimately had too many other commitments. Didn't stop her from being nominated for a Best Supporting Emmy for the show, though.
Also Lauren Lee Smith as of episode 3 of season 9. Impressive, considering she'd only just arrived the previous episode.
Most recently, we have Liz Vassey and David Berman, who were added to the opening credits in Season 10. (Lombard and Smith have since left the show, and Vassey's contract was not renewed for Season 11.)
On CSI NY, Robert Joy and AJ Buckley were both promoted to regulars in the last couple of seasons.
Neil Flynn on Scrubs, but only in the extended title sequence that was used for a few episodes of the second series until it was discarded after fans complained.
In season 1 he was an guest star, and from season 2 on he was promoted to one of the stars -though you wouldn't know it, since he's not in the opening sequence.
From season 2 on he was, however, listed among the main characters in the credits that appear at the bottom of the screen throughout the beginning of act 1 of every episode, instead of being listed among the guest stars in the end credits like he was during season 1.
Christopher Marquette and Becky Wahlstrom on Joan of Arcadia, both of whom were originally intended as one-episode characters.
The three members of the Mythbusters build team (the "Junior Mythbusters") are now mentioned in the title sequence alongside Adam Savage and Jamie Hyneman. This has the effect of making the slightly pointless introductory titles even longer.
For an couple of episodes a while back, the build team members were promoted to full Mythbusters in the credits. Also, strangely, the intern is not in the credits, despite the first one being of equal prominence to the build team.
Originally the end credits listed only Adam and Jamie as hosts; the others were just credited as just the "build team". But eventually the build team were bumped up to hosts as well.
ER's revolving door of doctors generally allowed one or two promotions per season, especially in the later seasons. A few that were notably not promoted included Laura Ceron as Chuny and Deezer D as Malik.
The cast members deemed important enough to rate the 7th Heaven opening credits change too often and too randomly to attach an adequate adverb to.
Autumn Reeser first appeared at the beginning of the third season of The O.C. as a minor villain. She soon turned into the Plucky Comic Relief and a friend of the main characters. When the fourth season started she was not only promoted, but ended up as the romantic interest of the protagonist.
This wasn't the first time the show had done this - Rachel Bilson (Summer Roberts), Melinda Clarke (Julie Cooper) were promoted to the opening credits halfway through season 1, while Alan Dale (Caleb Nicholls) was promoted at the start of season 2. Nor was Reeser the only recurring star promoted at the start of the 4th season; Willa Holland (Kaitlin Cooper) was added to the opening credits at the same time.
Doctor Who had no cast listing in the opening credits during its initial run, but upon its revival in 2005 the actors playing the Doctor and his companion were listed. The 2007 series marks the first time a 'secondary' companion has made the titles.
Jack and Mickey were ignored for their adventures in the first two seasons, but Jack was promoted for his three-episode reappearance in Series 3. Once that precedent was set, Freema Agyeman has been given her due in both series' credits (with the extra-special "And", no less).
In 2008, "The Stolen Earth"/"Journey's End" had a total of six actors (compared to the usual two) credited during the title sequence, forcing the names to rush past noticeably faster than normal. You can also see Gareth David Lloyd and Eve Myles from Torchwood and Tommy Knight from The Sarah Jane Adventures's names appear after opening titles as a kind of And Starring. The appearance of secondary roles are only seen in the end credits apart from this circumstance.
And speaking of Torchwood, the writers played with this one in the season 2 episode "Adam". The plot involved a Monster of the Week who inserted himself into the team's memories to seem as if he had been with them for years. Shots of him interacting with other characters were spliced into the usual title footage to add a bit of Mind Screw to the viewers' experience.
Bernard Cribbins and John Simm got this treatment for "The End of Time". The latter is the first time in the revival that a villain has shown up in the opening credits, albeit one who gets upstaged by Rassilon and ends up helping the Doctor.
Kai Owens was promoted to the opening credits for Torchwood: Children of Earth
During the course of Third Watch's run, Amy Carlson, Chris Bauer, Tia Texada, Nia Long, Bonnie Dennison and Cara Beuno were promoted to the opening titles.
In season two of Grey's Anatomy, Kate Walsh was originally listed as a special guest star but was later added to the opening titles as it became clear that her character would be staying in Seattle. (Which, of course, she didn't...but she got her own spin-off...
All of the later additions were promoted at least two episodes as a guest star.
Season 6 of ''Burn Notice sees Coby Bell (Jesse) finally moved into the opening. Though Gabriel Anwar has been in the credits since episode one, it bears noting that her character's relationship with Michael gets promoted as well: the narration now refers to her as "a trigger happy girlfriend" instead of "a trigger happy ex-girlfriend." It took more than a full season for Sam to be promoted from "friend who's informing on you" to "friend who used to inform on you" after he stopped informing on him. This show is very conservative with its opening title.
In the last season of Veronica Mars, much was made of recurring character Sheriff Lamb's ascension to the the status of regular character and a place in the opening titles. Then he was promptly Killed Off for Real.
Another recurring character, Mac (Tina Majorino), also got a spot in the opening titles for season 3. In what might count as a subversion, she didn't actually appear any more often than when she was a recurring guest star.
Ryan Hansen (who played Dick Casablancas) started as a non-speaking extra in the second episode and was bumped up to the opening credits by the Season 2 premiere, as was Kyle Gallner (who played his brother Cassidy Casablancas, aka Beaver) who appeared in the last three episodes of season 1. Note that the latter may not count, as the character of Beaver was introduced specifically to be the Big Bad of season 2, and thus was always intended for regular status.
In Stargate SG-1, there was a fan movement to get Dr. Frasier in the opening. (She got a bridge dropped on her instead, an offscreen death in an episode that was basically filler, though her memorial was one of the most touching scenes in the show's ten-year-plus-movies run.)
Dr. Carson Beckett from Stargate Atlantis fared better, though, making it into the opening partway into season two.
... And then got killed by an explosive tumor he was transporting. Not so lucky.
However, he returns, though not to the opening.
Season five promotes recurring characters Keller and Woolsey.
Stargate Universe gives us Ming-Na, who was promoted just in time for the midseason cliffhanger (the first part of which featured her character heavily).
Jeff Conaway, as Zack Allan, got promoted to opening titles in the third season after first appearing the previous year.
Another slightly different example is Patricia Tallman as Lyta Alexander: she was in the opening titles of the Pilot Movie, then left the show before returning for one episode of the second season and several episodes of the third season as a guest star, and was then re-promoted to opening titles from season four onwards.
In Smallville Lionel Luthor was a recurring character in season 1 but then was promoted to the opening in season 2-season 7. Similarly Lois Lane was only ever listed as Special Guest Star when she first appeared in season 4 but got promoted the following season oddly enough she appeared in the same number episodes as a guest character as she did as a main. 13 episodes due to restrictions made by DC.
Again with Green Arrow a recurring guest character in season 6 and 7 that became a main titles character in season 8.
Also Jimmy, who was a guest star throughout Season 6 and then promoted.
Liza Weil auditioned to become Rory Gilmore, but when she didn't get the role she was offered the Alpha Bitch role of Paris Geller instead as part of a short run to establish that Rory wasn't going to coast through Chilton. In lesser hands it probably would have been one note and out after the end of the original three-episode run. After season one however it was pretty obvious that Paris was going to remain a perpetual thorn in Rory's side forevermore, and Weil stayed a regular for the rest of the series.
Likewise Sean Gunn, who played Kirk, the man of many jobs who got on the regular cast roll after season two.
And a rotating regular position in the cast was open to whoever was the winner of the Rory Love Triangle that year, either Jared Padelicki, Milo Ventimiglia or Matt Czury.
And if any of the five above didn't appear in an episode, they didn't appear in the credits for that week.
Richard Kline on Three's Company. Jenilee Harrison was also promoted for season 6 after being Suzanne Somers' "temporary" replacement during her infamous salary dispute during season 5. Ironically, though, Harrison was seen less frequently in season 6 than season 5, and she was dropped from the show at the end of season 6.
Sean Murray (Tim McGee) Cote de Pablo (Ziva David), Lauren Holly (Director Jenny Shepard), and most recently Rocky Carroll (Leon Vance) of NCIS.
Brian Dietzen (Jimmy Palmer) was promoted to regular character and the opening credits starting with the 10th season. He played a recurring character on the show for eight years before that.
A lot of this is clear on JAG - Patrick Labyorteaux (Bud Roberts) and John M. Jackson (Admiral Chegwidden) were merely guest and recurring characters in the first season respectively before jumping to the main cast in the second year. The final season also saw this with Scott Lawrence (Sturgis Turner) and Zoe McClellan (Jennifer Coates). Catherine Bell, however, appeared as one character in the first season, then joined the main cast as another character in the second.
Iron Chef Italian Masahiko Kobe was eventually put into the opening title sequence.
Yin Yang Man appeared in the opening credits of the second season of WMAC Masters replacing the injured Panther, however this is also a bit of a subversion as his role did not increase in the show but another master that was not mentioned in the opening Warlock and a new master Tracer had much bigger roles as the (secret) antagonists but were not mentioned in the opening
Some episodes also featured Lady Lightning, Chameleon, and even the jobber Princess but only when the girls were fighting in an episode. Great Wolf, Star Warrior and Ying Yang Man where removed from the opening in those episodes
Heroes: Season 1 recurrers James Kyson Lee and Zachary Quinto were promoted for the second season. Season 3 promoted Cristine Rose, who had been recurring since the pilot. Additionally some have been promoted in the middle of their first season: Jack Coleman was promoted a few episodes into season one, David Anders was promoted around the time his character was revealed as Adam Monroe, and as of "Once Upon A time In Texas" this has occurred with Robert Knepper (though this was hyped up before the season even premiered).
Supernatural introduced Castiel in Season 4 and he was such a popular character that for the first time since the show started, a recurring character got promoted to regular status. Misha Collins (who plays Castiel) was originally contracted to appear in only 6 episodes in Season 4. He officially became a regular in Season 5. This is even more astonishing when you consider the fact that the accumulated screentime he got in Season 4 amounted to less than 3 episodes.
And then after being demoted in Season 7, he was promoted BACK to regular two seasons later.
After spending five seasons as a recurring character, Mark Sheppard (who plays Crowley) was promoted to regular for the 10th season.
The final season of Everybody Loves Raymond included Monica Horan (Amy) in the opening credits. After marrying Robert, she appeared in almost every episode.
The US version of The Office has two variants: characters who are promoted to the opening title sequence (Ed Helms in mid-Season 6 and James Spader in Season 8), and characters who are promoted to the main cast listed after the credits note Leslie David Baker, Brian Baumgartner, Kate Flannery, Angela Kinsey, Oscar Nunez, Phyllis Smith, Melora Hardin and David Denman in mid-Season 2, Mindy Kaling and Paul Lieberstein in Season 3 and Ed Helms in late Season 3, Creed Bratton and Craig Robinson in Season 4, Ellie Kemper in Season 6, Zach Woods in Season 7 and Amy Ryan in early Season 7, Catherine Tate in mid-Season 8, Clark Duke and Jake Lacy in Season 9. Whew..
Recently changed, updating images of cast and including other cast members, though many appear only in group shots.
The Battlestar Galactica (Reimagined) opening title credits remained the same for all four seasons, but its list of secondary stars (an intermediate step above guest stars) saw two promotions: Nicki Clyne as Cally Henderson Tyrol in season 2 and Michael Trucco as Samuel Anders in season 4.
Subverted in House, where the opening credits remained the same from season 1 to 6, despite the fact that by season 4, Peter Jacobson (Taub), Olivia Wilde (Thirteen), and Kal Penn (Kutner) have comparable "face time" (if not more) as any of the named stars and Jennifer Morrison shifting to guest star status in all but name.
As of season 7, the intro has finally been updated to take out Morrison and add Jacobson and Wilde.
And then Wilde disappeared for the first half of season 7 to film TRONand has been replaced in all but name by Amber Tamblyn.
Voice actors Jonathan Hardy and Lani Tupu in Farscape were never credited in the main title. In season three, however, recurring character Crais, also played by Tupu, was promoted to lead status.
In more standard examples, Gigi Edgley (Chiana) was added to the opening credits a couple of episodes after her introduction, and Wayne Pygram (Scorpius) and Paul Goddard (Stark) were also promoted in the third season. Controversially, the female regulars added in seasons three and four, Tammy MacIntosh (Jool), Melissa Jaffer (Noranti), and Raelee Hill (Sikozu), never got added to the opening credits despite appearing in more episodes of their respective seasons than Paul Goddard did in the third.
While it doesn't have opening titles as such, Greek added Tiffany Dupont (who played Frannie) to the "Starring" credits midway through Chapter 2. Given that the show is being cancelled at the end of the 4th season, she will likely hold the somewhat unusual honor of being the only character to be promoted to regular status and the only regular character to be written out during the entirity of the show's run.
Alias promoted several recurring characters to the opening credits over the years, specifically recurring villain Sark (David Anders) at the start of season 2, wise-cracking CIA agent Eric Weiss (Greg Grunberg) at the start of season 3 and Sydney's long-lost sister Nadia Santos (Mia Maestro) at the start of season 4 and Shed operative Kelly Peyton (Amy Acker) midway through season 5. While Maestro was introduced late in season 3 specifically to serve as a regular character the following season, the others were promoted due to fan popularity. Grunberg is particularly notable as, despite featuring in more than half the episodes in season 1, he wasn't even credited as a guest star until the start of season 2.
Garcia gets bumped up to the credits when Lola Glaudini left the Criminal Minds cast.
Actually, Vangsness (Garcia) was promoted at the beginning of Season 2, having previously been bumped up to "Also Starring" in the back nine of Season 1. Glaudini left in the sixth episode of the season. A better example would be Rachel Nichols in Season 6, who was a guest star for two episodes before being promoted to fill the void left by AJ Cook (who left in Episode 2), and the soon-to-depart Paget Brewster (who left in Episode 18)
Cook and Brewster were restored to the cast in Season 7, the former having made a few post-leave guest appearances.
A strange—and probably planned—one occurs in Mad Men, wherein Kiernan Shipka, the 10-year-old child actress who plays Sally Draper, was promoted to opening titles in Season 4. From interviews and the general course of the show so far, we'll be getting a lot of Character Focus on Sally in episodes that include the Draper family arc (which isn't all of them now that Don and Betty are divorced).
In the same way, Tinka from Shake It Up got it too in the same season as Rico's.
Ron Glass, Jack Soo, Steve Landesberg, and Ron Carey in Barney Miller.
Rex Lee (Lloyd) got promoted to opening-credit status on Entourage.
Greg Proops (Mr. Madigan), Ron Butler (Oscar) and Rob Arnell (Jimmy) on True Jackson VP.
Jon Cypher finally got promoted to the opening credits about midway through season 2 of Major Dad.
Edward Platt as the Chief was added to the opening credits for the second season of Get Smart.
Richard Genelle as Ernie, who had been a recurring character since Mighty Morphin' Power Rangers season 1, and Gregg Bullock as Lt Stone, who first appeared in season 3, both got added to the titles for the fourth season, Power Rangers Zeo. And in season 2, Steve Cardenas as Rocky, Johnny Yong Bosch as Adam, and Karan Ashley as Aisha, were added to the titles only after becoming rangers, even though they debuted 7 episodes earlier.
Jim Rash (Dean Pelton) has been promoted as of Season 3 of Community.
On The Cosby Show, Sondra, Cliff and Clair's eldest, only showed up in a few episodes of the first season, but she was promoted to a regular character in the second season, although she was not often seen. Other characters followed in subsequent seasons.
The Vampire Diaries had this with Klaus, who was a recurring character in the second season, but starting season 3 Joseph Morgan is found in the credits along with the other regulars, lasting until the end of season 4 (since his character got his very own spin-off).
A rare example with Nina Dobrev: While she has been part of the main cast since the pilot, portraying the show's protagonist Elena Gilbert, she also portrayed the recurring character Katherine, Elena's doppleganger/vampire ancestor. As of season 5, Katherine is upgraded to main character as well, so Nina is credited twice.
Boy Meets World: Danielle Fishel (Topanga) in season 2, Lindsay Ridgeway (Morgan #2) in season 4, and Trina McGee-Davis (Angela) in season 6.
Taxi added Christopher Lloyd (Jim Ignatowski) to the opening credits in the tenth episode of season 2, while Carol Kane (Simka) was added at the beginning of the fifth and final season.
Blossom is a partial version. While the core cast never really changed, the opening titles of the third and fourth seasons had the rest of the characters appearing onscreen with Blossom, instead of just having Blossom dancing by herself.
Played straight with the addition of Jenna von Oy to the cast. When the show debuted, von Oy had also (in addition to her role as Six LeMure) been cast in the short-lived CBS sitcom Lenny (both shows sharing the same creator and production team). When the latter was canceled, Blossom was already into its first season; thus no promotion until season 2 (the show's first full year; as it debuted as a midseason replacement).
Teen Wolf: Season 4 promoted recurring actresses Arden Cho (Kira Yukimura) and Shelley Hennig (Malia Tate) to main cast after Crystal Reed chose to leave the show for personal reasons.
24 has done this for numerous recurring characters with each successive season. It happened with Xander Berkley, Penny Johnson Jerald, and Carlos Bernard for season 2; Reiko Aylesworth for season 3; Lana Parrilla and Roger Cross midway through season 4; Mary Lynn Rajskub, Carlos Bernard (again), Gregory Itzin, James Morrison, and Louis Lombardi for season 5; D.B. Woodside, Jayne Atkinson, Carlo Rota, and Eric Balfour for season 6; and Bob Gunton for season 7.
Of note, just about any recurring actor or actress who appeared through an entire season give or take an episode (Bernard and Jerald in season 1, Aylesworth in season 2, Rajskub and Woodside in season 3, and Lombardi in season 4), they would generally get promoted to the show's main cast in the following one. Notably, unlike the others Mary Lynn Rajskub and D.B. Woodside actually both appeared in a second season while still part of the recurring cast before finally getting a promotion to the opening titles. In an interesting aversion, Zachary Quinto also appeared in nearly the entire third season (he only missed one episode), but notably never appeared again in the show after that.
Game of Thrones: Six recurring characters in Season 1 got promoted for Season 2: John Bradley (Samwell Tarly), James Cosmo (Lord Commander Jeor Mormont), Jerome Flynn (Bronn), Conleth Hill (Varys), Sibel Kekilli (Shae), and Charles Dance (Tywin Lannister). Oona Chaplin (Talisa Maegyr), Rose Leslie (Ygritte), and Joe Dempsie (Gendry) are promoted in season 3. Kristofer Hivju (Tormund Giantsbane), Gwendoline Christie (Brienne of Tarth), Iwan Rheon (Ramsay Snow), and Hannah Murray (Gilly) are promoted in Season 4.
Person of Interest: Kevin Chapman was always a series regular, but his character, Detective Fusco, is finally included in the opening titles during the last few episodes of season one.
Root was promoted to the opening credits partway through the third season when she resumed an active role as a Hero of Another Story.
Tinsel: Ireti Doyle is finally included in the main cast in the last quarter of Season 4, which takes the wind out of any fan speculation that her character, Sheila, will be living the show any time soon.
Royal Pains: As of the fourth episode of season four, both Brooke D'Orsay (Paige) and Campbell Scott (Boris) have been upgraded to the opening credits, replacing Jill Flint (Jill Casey), who was Put on a Bus in the previous episode.
In Dexter, Jamie Batista (who was a recurring character in season 6 and 7) and Tom Matthews (recurring since season 1) were both promoted to series regulars in season 8, the last season of the show.
Back in season 2, Masuka goes through this as well, after being in pretty much every episode of season 1.
Once Upon a Time: In season two, Meghan Ory (Ruby/Red) and Emilie de Ravin (Belle) were both promoted to series regulars. Eion Bailey (August) and Raphael Sbarge (Archie/Jiminy Cricket) were Demoted to Extra.
Colin O'Donoghue (Hook/Killian Jones) also gets promoted halfway through season two, after his few appearances early on that season earned him Ensemble Darkhorse and Draco in Leather Pants status among the fans.
Michael Raymond-James, who plays Neal (aka adult Baelfire), was promoted to series regular for season 3, while Meghan was Demoted to Extra as she got cast as the lead female character in Series/Intelligence2014
Homeland promoted several actors to the opening titles for it's second season, though some of them actually featured in less episodes than they did as guest stars in the first.
Starting in season 6, Amy and Bernadette are included in the title sequence of The Big Bang Theory, eating with the main characters in the scene just before the main title.
Before getting their own show, The Simpsons were promoted to the opening titles of The Tracey Ullman Show in the third season. They were promtly demoted when their show premiered and their segments were dropped.
Charmed: Brian Krause (Leo Wyatt) was promoted in season 2 having been a recurring character in season 1, and Drew Fuller (Chris Halliwell) was promoted for season 6 having been a guest star in the final two episodes of season 5. As with all other regulars on the show, they are still only in the opening credits for episodes they actually appear in.
Smash: Kinda-example with Leslie Odom Jr. (Sam Strickland). Having been a recurring character in season 1, he's a regular for season 2, but is one of three regulars who don't get an individual title spot; instead, they appear in brief flashes at the end of the credit and get an "Also Starring" credit before each episode's guest stars.
Terry Bellefleur from True Blood gets this in season 2, after his recurring role in the first season. Same case with Jessica, who was introduced in a few episodes of season 1 and became a main character in the second as well. And the same applied to Pam and Eric too.
Nan Flanagan was a recurring character who had very few appearances until season 4, in which she is made a regular as well.
Steve Newlin was a secondary antagonist for the second season, and later at the end of season 4. He's credited as a main character season 5 onwards. His wife (later ex-wife, later enemy) Sarah got promoted to series regular in season 6.
Sons of Anarchy: Jimmy Smits (Nero) has been announced to be this in Season 6. Prior to that, Ryan Hurst (Opie), William Lucking (Piney), and Theo Rossi (Juice) were this in Season 2, and Dayton Callie (Unser) was this in Season 3.
Parks and Recreation promoted Retta (Donna) and Jim O'Heir (Jerry/Larry) to opening credits halfway through season 6, after the departure of Rashida Jones (Ann) and Rob Lowe (Chris).
Arrow promoted three of its recurring cast members to regulars for its second season: Emily Brett Rickards (Felicity), Manu Bennett (Slade) and Colton Haynes (Roy). Season three has John Barrowman (Malcolm) promoted to regular status after being recurring in the first two seasons.
Evelyne Brochu was upgraded from recurring character to opening title lister in season 2 of Orphan Black
In Night Court, Markie Post guest starred as Public Defender Christine Sullivan in an early season 2 episode, then returned in the third season onward as a series regular. Florence Halop and Marsha Warfield respectively guest-starred in the 3rd and 4th season premieres before being promoted to regular status in the following episode.
Due to the ever changing nature of pro wrestling, you could see people who are featured in one week's opening of shows like WWE Raw and Smack Down not be featured in the next. Usually the changes are not as frequent as that, but because of things like contracts expiring and fallouts, they can happen suddenly. However, being on the intro to these shows for an extended period of time is a major feather in the cap of some wrestlers.
After the (story line) firing of John Cena in 2010, the intro to Raw was replaced by The Miz (who was the WWE Champion at that time). Even though The Miz was in the intro before this, he was promoted to a coveted spot in the intro: as the final wrestler being shown. It was John Cena that was the last shown during the entire run of the "Burn It To The Ground" intro, which made it a huge leap for The Miz.
The WWE Signature vanity card can count for an intro, as well, and the "Power is Back" version was only changed three times, each time because those that were replaced either went to TNA or had done something to piss Vince McMahon off. Because of this, a few were promoted to the Signature as having lines. Ted Di Biase replaced Hogan when the latter went to TNA, John Cena was added to the end, and Michael Cole replaced Jim Ross. After the additions of Cole and Cena, the audio wasn't changed again for the rest of this Signature's duration.
As progress is made in the 10th Fire Emblem title the Greil Mercenaries and the Black Knight will appear in the intro.
For the series as a whole, if left to sit at the title, various games in the series will detail classes. Additional classes are shown after extra playthroughs.
After being unlocked, hidden characters in the original Super Smash Bros.. and its sequels appear in the opening.
Specifically, the four unlockable characters are originally silhouettes in the first Smash game, and in Brawl, unlocked characters are added to the line of characters standing over a cliff near the end of the opening (though Marth and Ness make appearances in the Subspace Emissary movie clips, and the Green Hill Zone stage makes an appearance in the opening.)
Sonic and Snake both have to be unlocked but are shown in the opening, though in game play shots.
Melee only has one opening that doesn't change. Ganondorf, Pichu, and Jigglypuff are the only ones to show up (Ganondorf pokes his arm in during the The Legend of Zelda segment to help form the Triforce, while Pichu and Jigglypuff leap in front of the other Pokémon during the Pokémon segment).
Blaster in The Transformers was promoted to an appearance in the opening for season three despite being a recurring character throughout season 2 and playing a prominent role in the first half of the movie.
For the second season of DuckTales, a few different episode clips were used than the ones from season 2 to prominently feature its two new major characters, Bubba Duck and Fenton Crackshell/Gizmo Duck.