The two main heroes of the Arrowverse fit this. Oliver Queen/Green Arrow is The Stoic, analytical, and reliant on his precision in archery. Barry Allen/The Flash is more emotional, idealistic, and blitzes through his enemies and life with his Super Speed.
The deathly cold White Walkers and the fire-breathing dragons and fire-themed Lord of Light.
The honorable Starks and the pragmatic Lannisters.
The Stoic, grim, peace-loving Blue Ned Stark and the boisterous, hedonistic Red Robert Baratheon.
Arya is the gutsy, extroverted red to Gendry's calmer, introverted blue in Season 2 and 3. (Ironically inverting the dynamic in their father's friendship as Ned was blue to Robert's red). She gets colder and more emotionless in later seasons.
Though arguably they're both blue oni, just with different goals; whomever they're helping/pretending to help is their red oni du jour. (Varys blues to the reds of Tyrion and Daenerys, Baelish to Sansa and Cersei. Both bring out Ned's rare red moments.)
Brandon was the reckless, Hot-Blooded Red to his brother Ned's patient, soft-spoken Blue.
Kinda, with House Clegane. Sandor isn't exactly serene and emotionless, but he's much more stoic and in control of himself than Gregor. Emphasised by their fight at the Hand's Tourney, when King Robert orders them to stop, Sandor immediately drops to one knee (handily ducking Gregor's swing), while Gregor tosses aside his sword and storms off in a rage.
Joffrey serves as the violent, impulsive, sadistic Red Oni to the calm and intellectual Tyrion, the cold and calculating Tywin, and the meek, soft-spoken Tommen.
Tyrion is the blue to Jaime's more hotheaded red.
Grange Hill has several examples: Tucker Jenkins is red to Alan Humphries and Benny Green's blue. Mrs Mc Clusky is blue to both Mr Keating's and then Mr Bronson's red. Gonch Gardner was red to Hollo's blue. Pogo Patterson was red to Duane Orpington's and Stewpot Stewart's blue. Then among the girls, Trisha Yates was red to Cathy Hargreaves' blue, Suzanne Ross was red to Claire Scott's blue and Annette Firman was red to Fay Lucas' blue. Although all three of those female blue onis did go off the rails at some point.
Doctor Who has this many times between the Doctor and his companions, but here are the notable examples
The adventurous but grumpy First Doctor is the red to the blue of the level headed and educated Ian and Barbara
The red of the mischievous and bumbling Second Doctor to the blue of the intellectual Zoe
The red of the arrogant and dashing Third Doctor to the blue of the young and innocent Jo
The red of the kooky and strange Fourth Doctor to the blue of the even smarter and cautious Romana.
It's the other way around with the Fifth Doctor. The Fifth Doctor is the calm and collected blue to the red of the snarky Tegan.
The red of the stubborn and melodramatic Sixth Doctor to Peri's blue.
The Seventh Doctor and Ace constantly switched around with this, with the Seventh Doctor being more level headed than Ace, but Ace the more moral of the two when the Seventh Doctor was masterminding an elaborate scheme.
The red of the eccentric Eighth Doctor to the doubtful Grace.
The trauma-ridden and impulsive Ninth Doctor to the compassionate Rose Tyler.
The red of the bombastic Eleventh Doctor and the feisty Amy to the blue of the more down-to-earth Rory.
The red of the sarcastic and snarky Twelfth Doctor to the blue of the caring Clara, which was even lampshaded in "Into the Dalek". This is soon played with Series 9, with Clara becoming more red due to her reckless nature, which is what eventually leads to her demise.
The red of the passionately optimistic Twelfth Doctor in the Lie of the Land to Missy and Bill's blue, where Missy's well-reasoned but still coldly blunt suggestion, essentially putting Bill into a coma is considered reasonable by Bill, and she eventually attempts to enact this solution by trying to overwrite the Monk's psychic signal and burning her own brain out despite the Doctor's conviction that there is another way where everyone lives. She manages to do it without burning out her brain.
Kamen Rider Kuuga has happy-go-lucky and brave Yuusuke Godai (Kuuga) and calm and cool Kaoru Ichijou (a cop that helps Godai)
Even more, the armor of Kuuga's main form is red, which matches Godai's personality. He actually can change into an alternate form, which is blue-colored, but he also has a form that is colored purple.
Western adaptation Kamen Rider Dragon Knight also qualifies, though Kit Taylor (Dragon Knight) isn't as Hot-Blooded or impulsive as most Red Oni; he really only looks a little that way when compared to Len (Wing Knight).
Kamen Rider Blade has Blade as the Red Oni (and The Hero) and Garren as the Blue Oni (and The Lancer). Played with in that their main colors are the opposite of their personality (Blade, the Red Oni, is mostly blue in color, while Garren, the Blue Oni, is mostly red.)
Kamen Rider Kabuto has Kagami Arata and Tendou Souji, who fit the trope to some extent, but with some notable exceptions:
The blue oni, Tendou, is the main hero.
Any victories that Kagami achieves are won at length and through actual effort, not handed to him for free by virtue of Dumb Is Good.
The colours of their suits are reversed: Kabuto (Tendou) is red and Gatack (Kagami) is blue.
Kamen Rider Den-O has Momotaros, the red oni looking one, who loves the thrill of a good fight. Then there's Urataros, the blue one, who keeps cool at all times and prefers to use deception to get out of sticky situations and score chicks.
Kamen Rider Decade has Tsukasa/Decade and Daiki/DiEnd, although Tsukasa is normally more blue in personality...until Daiki shows up. Their suits mostly match their roles, although Decade is magenta, not red.
Kamen Rider W gives an interesting triangle. While Philip almost-always plays Blue Oni to both Shoutaro and Terui (if Philip is playing Red Oni, then you know it's a bad situation), Shoutaro's "hard-boiled yet passionate" and Terui's "cold and distant yet volatile" personalities regularly has them switching roles, depending on who's Red at the moment.
W's only red/blue combination is HeatTrigger, which inverts Philip's and Shoutaro's colors.
Accel's suit starts out red, but his power-up of Trial Mode is blue. This actually mirrors Terui calming down as the series progresses.
Although Justin and Alex, from Wizards of Waverly Place, are both sarcastic and, to an extent, Deadpan Snarkers, they have really different personalities. While Alex is witty, prankish, and lazy, never taking anything seriously (represented by red), her older brother, Justin, is responsible, much more mature, studious, and collected (represented by blue).
The interesting thing is that in their wizard competition, they reversed the associated elemental roles, with Justin showing more of an affinity for fire, while Alex tended to use water.
Many Super Sentai and Power Rangers series have the Red Ranger as a Red Oni, and several have the Blue Ranger as something of a Blue Oni. Few have their relationship as a major theme, though.
Tokusou Sentai Dekaranger has Ban Akaza, the Red Ranger/Oni who is chaotic but friendly, and Hoji Tomasu, the Blue Ranger/Oni who is professional but arrogant. The American version, Power Rangers S.P.D., does the same with Jack Landors and Sky Tate, although Jack does not embody Dumb Is Good to the same extent as Ban.
Choushinsei Flashman reverses colors with its duo: Jin, the Red Flash, is the more sensible and mellow Blue Oni, whereas Dai, the Green Flash, is the strong, arrogant, and frightening Red Oni.
Another Example is Samurai Sentai Shinkenger, Same as Jetman and Zyuranger, colors are reversed: Takeru (The Leader) is the Blue Oni who is more sensible and cautious yet he always calculate when it comes to decision and planning but wears red with fire element and Ryuunosuke (The Lancer) is the Red Oni who is impulsive and emotional and most likely to jump into conclusion instinctually and bring the situation livelier for fun but wears blue with water element.
Mighty Morphin' Power Rangers fit the trope to an extent - the Red Ranger was the confident, extremely physical leader of the band while the Blue Ranger was the intellectual brainiac of the bunch.
Of course Kyoryu Sentai Zyuranger is rather different from its American adaptation - Tyrannoranger Geki is calm and smart by default, as Triceraranger Dan is dumb, brash, and wanting to rush into a fight.
Whenever the Power Rangers writers get lazy and make the Rangers expies of Sentai, the theme shows up more. Often Sentai will have the Hot-Blooded Red who lives by Don't Think, Feel and the calm expert Blue. Power Rangers tones down the loud screaminess of the Reds but falls back on Rookie Red Ranger to the point that the dynamic is the same: a Red who's winging it and an expert Blue, who's actually more likely to be annoyed with Red than in Sentai. It's worse when the Rookie Red is given formal authority. (See, it's known that Red is "always" the leader, but half the time, "Leader" seems to mean "Red stands in the center for the "Super Sentai" Stance because it's habit." Nobody ever actually said Leo or Mack were in charge of anything; but in SPD and Wild Force, that's not the case, and the guy who doesn't know what he's doing outranking the one who does is a way to keep the friction going for quite some time.)
In the French series Les Petits Meurtres d'Agatha Christie, reporter Alice Avril is the Red to Commissaire Laurence's Blue. Their costumes even lampshade this; Avril wears a red leather jacket and Laurence's suit is usually blue.
Jack O'Neill and Dr Daniel Jackson from Stargate SG-1 could fit into this trope as many of the earlier episodes' conflict came from O'Neill's emotional pragmatism conflicting with Daniel's intellectual desire to study and understand various things. Interestingly, this is often reversed in later seasons - Jack descends into rational, Black-Ops mindset as Daniel plays up his I-empathize-with-everyone side.
Ronon and Teal'c have this kind of relationship in the Stargate Atlantis episode "Midway". Ronon being the aggressive and wild Red Oni and Teal'c being the calm and cultured Blue Oni. And both being The Big Guy of their respective show.
Rodney McKay is Red Oni to almost any other scientist that appears on the show, notably Zelenka, Beckett, and Beckett's replacement and McKay's love interest, Dr. Keller.
Unusual in that Rodney is usually smarter than his Blue Oni, which makes up for his often-times unscientific professionalism. When he plays opposite Samantha Carter, who is the only scientist in the SGC that he accepts as being better than him, McKay plays a bit more traditional Red Oni.
On Judge Judy, a calm woman with dyed-blue hair sued an angry woman with dyed-red hair.
Firefly loves playing with this trope and stretching the boundaries of it as far as they can go, sometimes with mind-bending results.
Mal and Simon are set up at the start to look like Red Oni and Blue Oni; Simon's even set up to look like a villainous Blue Oni. Then the truth is revealed and from that point on, it's very clear that while they superficially look like an ideal Red Oni, Blue Oni example, they're actually a case of Not So Different, as Simon is every bit as passionate and willing to break the rules and law as Mal. As it turns out, he's even got a better talent for crime than Mal - at least, when it involves a subject he's familiar with.
Jayne and Simon have an equally interesting dynamic. Their Red Oni, Blue Oni relationship is deliberately used to play them against each other in almost every scene they share. However, who is Red and Blue actually changes depending on the situation. For all of Jayne's hot-headed, uncultured nature, he's also a very level-headed Combat Pragmatist with sometimes surprisingly accurate assessments of people and situations. This is often used to compare and contrast with Simon's cultured intellectualism that only superficially masks his deeper passion and idealism.
In a similar sense to Simon and Jayne, Jayne's pragmatism is sometimes used to play villainous Blue Oni against Mal's heroic Red, especially with regards to the issue of keeping Simon and River on the boat. No-one can deny the sheer logic of Jayne's attitude, but Mal's far too compassionate to be swayed by it.
And yet at the same time, Jayne's immediate recourse to violence, his impulsive nature with money or loyalty, and his immediate, snap dislike of Simon (contributing to his attempt to get him off the boat ) makes him a pretty good candidate for Red. They play the roles very well, but the Red/Blue divide mostly seems to depend either on the issue at hand, or which characters eyes you're seeing it through.
Mal's most obvious Blue Oni counterpart is Zoe, who is also a Blue Oni to her husband's Red Oni.
There's also one going between Simon (Blue Oni) and Kaylee (Red Oni).
To an extent, this also applies to Mal and Shepherd Book. Although Book has a somewhat rough, earthy nature akin to a red oni, he is also a very intellectual, spiritual, and cultured individual. Besides that, there's his heavily hinted past with the Alliance, which is about as blue an organization as you can find.
This trope fits very well with Lost. Jack - though a doctor, which is very blue in nature - is a very passionate, people-oriented, and frequently rebellious leader. Locke, on the other hand, is more preoccupied with spiritual matters, such as destiny and purpose, as well as more learned in a greater variety of fields. Interestingly enough, though Locke has also frequently shown signs of the blue oni villain through his coldness towards others, Jack's ruthlessness is far more potent, as depicted when Locke cannot bring himself to shoot Jack in order to stop him from talking to the freighter people, but Jack is fully willing to shoot Locke when the two next encounter each other.
Though, when it comes to classic Evil Blue Oni, it's pretty hard to match Ben.
And Sawyer is both in one person!
Peter and Nathan Petrelli from Heroes. Nathan takes the role of the Aloof Big Brother while Peter is the younger, emotional, and, unfortunately for many, an Idiot Hero. Also, Peter and Sylar, according to how their powers work (Peter's is empathy, Sylar's is intuitive aptitude). However, in Season 3, Peter absorbs Sylar's ability, making him have the hunger, and Sylar has had Peter's ability all along. Also deconstructed in a future episode, where Peter summons fire while Sylar summons ice. It makes even more sense since Peter and Sylar are revealed to be brothers.
Except it's later revealed that was just a lie and they are, in fact, not brothers.
Also, if you compare the heroes with their future selves, who are all apparently badass. It's inverted in the case of Sylar, where he moved into Claire's home, calls himself Gabriel (his real name) and is much nicer than his present self. He even has a son named Noah.
Inverted in the case of the siblings Meredith and Flint. Meredith has the red fire, but she is much calmer and more level-headed than her younger brother, who's about as bright as a flea but has the blue fire. However, since Meredith is on the side of good, she possesses a genuinely warm (pardon the joke) and caring personality for her family while her brother is ruthless and even killed a woman with his powers.
Also, in an early first-season episode, Mohinder and Sylar are speaking about Mohinder's father (who was actually murdered by Sylar, unknown to Mohinder). At first, both are lit by a blue-green light, but when the murder comes up, Sylar turns away from Mohinder and smirks, and his face is lit in a red light. Mohinder's still in the blue light.
This dynamic plays out with several characters in The Wire:
Jimmy McNulty and Bunk Moreland possess this dynamic: McNulty's a free-wheeling Cowboy Cop who yells, cusses, gives a fuck when it ain't his turn to give a fuck, and generally plays by his own rules, whereas Bunk is quiet, direct, and by the book.
Avon Barksdale and Stringer Bell possess this as well. Avon's the shrewd but hotheaded leader of the Barksdale organization, while Stringer generally seeks to avoid conflict and instead see the practical side of things, and attempts several times to make legitimate business pursuits.
Homeless heroin addict Bubbles is the Blue Oni to his more impulsive friend Johnny Weeks and later to naive protege Sherrod. Both Red Onis die due to their incautious nature while Bubbles escapes the street.
Felicia "Snoop" Pearson and Chris Partlow, the enforcers for up-and-coming drug dealer Marlo Stanfield in Season Three, also form this dynamic. However, the one time Chris truly loses it, even Snoop is amazed.
Jed Bartlet (red) and Leo McGarry (blue) from The West Wing fit this trope to a tee — in fact, a good portion of Leo's job is to act as Bartlet's cool-headed, hard-nosed, deep-thinking Blue Oni counterpart, pulling the passionate, sensitive, deeply moral, and idealistic President back from the brink with logical arguments when he gets too angry, vengeful, excited, righteous, irrational, or quixotic.
Spock (fittingly costumed in blue) is a classic blue oni on Star Trek: The Original Series; on the occasions when they're not all chumming it up as a Power Trio, Kirk and McCoy each often serve as the red oni to his blue, depending on who's playing off whom at the moment. Red and blue aren't specifically used as contrasting colors for them—McCoy wears blue as well—but their red human blood and his "cooler"-colored green Vulcan blood are often contrasted.
According to Shatner's autobiography, one problem they had with the original pilot, The Cage, is that Captain Pike and Mr. Spock were too similar. If you were going to have an unemotional Mr. Spock, then the captain needed to be very emotional so that they could play off of each other, and that's how Shatner played him. Also, the show originally was meant to be Kirk and Spock, and the Kirk/Spock/McCoy trio developed on its own. (Note that only Shatner and Nimoy have "I get what he gets" clauses in their contracts.)
However, in "The Cage", Spock wasn't unemotional at all. It was Pike's first officer, Number One, who was logical and calm, cool, and collected.
Also, the show buys into this trope in a more general way: science and medical personnel, the knowledge-oriented "brains", wear blue, while operations; security and engineering, the action-oriented "brawn," wear red.
In Star Trek: Deep Space Nine, we have the rival temporal beings the Prophets (very cold in their interactions, theme color blue, basically "good" if kind of confusing about it) and the Pah-Wraiths (subtle about nothing, spewing red flames all over the place, unmistakably evil).
In a more general sense, the Federation (blue) and the Klingons (red) fit this pretty well in the 24th century, including the color scheme (for instance, the graphics used for their transporters and their emblems).
Despite that Worf is a blue Klingon and Jadzia is a Red Starfleet officer.
Jadzia is the blue oni in her friendship with Kira - Jadzia often being more level-headed and relaxed, while Kira is...Kira .
In any episode featuring the Mirror Universe, the mirror characters are quire literally the Red oni to the main series' Blue. However, only in Star Trek: Deep Space Nine do characters actually meet their mirrors in person.
iCarly has red Sam and blue Carly, red Sam vs. blue Freddie, Spencer vs. the community art teacher....
While not on the same shows (or even the same channel), "dueling" chefs Buddy (Cake Boss) and Duff (Ace of Cakes) have opposite personalities: Buddy is extremely Hot-Blooded while Duff is considerably more relaxed; this extends to their surroundings: Buddy's bakery is a neighborhood institution and is mostly staffed with his family (including his four older sisters) while Duff only does specialty cakes and is surrounded by his friends.
The promos for both of these shows does the same. The promos for Cake Boss are usually with a warm reddish background, with the famous red TLC logo. In contrast, most of the promos for Ace of Cakes are done in shades of blue and even color the Food Network logo blue.
Blake's 7 has two pairs of these, one on each side, for the first two seasons: red oni Roj Blake, passionate freedom fighter, frequently reckless, and his Lancer, blue oni Kerr Avon, coldblooded "what's in it for me?" tech, versus blue oni Servalan, primary power of the evil Republic, and her revenge-obsessed red oni, General Travis.
In season 3, with Blake vanished, Avon ends up stuck with red oni/brash youth Tarrant while fugitive Servalan doesn't bother to replace the dead Travis.
A Disney Channel movie called "Stepsister from the Planet Weird" had this for the two families: the down-to-earth Earthlings were blue while the literally air-headed (they're bubbles) and overly emotional aliens were pink/orange. Naturally, their wedding theme was purple.
The Casablancas brothers: Dick is stupid, impulsive, never thinks things through, loud, and sex-obsessed. Beaver is intelligent, quiet, reserved, manipulative, secretive, and completely ruthless.
Logan and Duncan. Duncan (blue) is reserved and somewhat emotionally restricted, whereas Logan (red) is pretty much the dictionary definition of Hot-Blooded.
And, in flashbacks, Lilly and Veronica. Lilly was the brash, wild one (red), whereas Veronica was sweet and demure (blue) before (things changed).
The Persuaders!, an English crime series, has two main characters: the aristocratic Brett Sinclair (Blue), who is cultured, clever, charming, and has a dry British humor, and Danny Wilde, a self-made American rich (red), who is hotheaded, uncultured, and very enthusiastic.
Both shows have this with the vampires Spike and Angel. The former being Red, the latter being blue. Especially in Season Five of Angel.
Also, Buffy and Kendra. Kendra seems to be blue to Buffy's red because she's a more classically trained by-the-book slayer yet her lack of experience and gung-ho attitude puts her on the red.
Faith and Buffy after Kendra dies. And maybe Willow and Tara in season six.
When Willow and Tara first meet in Season 4, Tara wears blue and Willow wears red — Tara is shy, cautious yet with longer experience in magic use, while Willow is more powerful, impulsive and (by that stage) outgoing in personality.
Halfrek is more easygoing and worldly compared to the workaholic and awkward Anya.
A nice example in Homicide: Life on the Street with the duo Bayliss/Pembleton. Bayliss is a somewhat Emo young man who is tragically unable to keep emotionally distant from his job and is given to outbursts of violence, but is also caring and sensitive. Pembleton is an older, smarter, educated, cold, and occasionally smug professional.
At the end of the pilot of Leverage, you see a group shot in which the two most hot-headed and aggressive of the crew (Nate and Eliot) have on red ties, and the two most calm and collected members of the team (Sophie and Hardison) are wearing blue. Of course, Parker, being the resident sociopath, has no color scheme.
Dean and Sam from Supernatural are red and blue, respectively, especially during the first season.
Except, as Character Development marches on, they switch places: Sam is revealed to be much more hotheaded and reckless, and Dean revealed to be more of a stoic. It's most obvious when you compare their reactions to each other dying. Dean cries perfect, single Manly Tears and asks Sam what he's supposed to do now. Both times Sam is faced with Dean's death (in "Mystery Spot" and during the four months before Dean was resurrected), he cries first but soon after sets about avenging him.
As of season 9 onwards this trope is taken Up to Eleven, with Sam as the coolheaded Blue Oni who tries to take care of Dean's (extremely) Hot-Blooded Red Oni. Doesn't exactly helps that Dean was a demon through season 10.
Saturday Night Live gave us loud, cocky Wayne Campbell (red) and shy, nerdy Garth Algar (blue).
In Unnatural History, there's the adventurous, bold Henry Griffin (red) and his level headed, stick to the status quo cousin Jasper (blue).
On 24, Jack Bauer and Tony Almeida play these roles to each other - with Jack as the Rabid Cop red oni and Tony as the (relatively) controlled, business-like blue oni.
Keen Eddie: Eddie Arlette and Monty Pippin take turns with who is what. In their work, Monty is blue and Eddie is red, while in their private lives, it's the other way around.
The Mighty Boosh: Many characters pair off and start redding and bluing it up, especially anyone in a conversation with Naboo, the show's resident Blue Oni. Howard and Vince often play with the red and blue chemistry, but they're more like a couple of purples putting up a front.
Fiona and Michael have been this since the very start in Burn Notice. Now that Jessie has been added to the team, (who is both a male Red Oni and also a spy like Michael) it brings up all sorts of interesting chemistry, not to mention the vastly different approaches that Jessie and Michael bring to their job.
The main stars of MythBusters, Adam Savage and Jamie Hyneman form up very solidly into these characterizations. Adam is exuberant and emotional, often laughing and exclaiming while on the job. Jamie is stiff, cool and analytical, always in control of himself. Behind the scenes, they admit that their completely incompatible personalities had prevented them from becoming friends in spite of their professional respect for each other.
Merlin and Arthur, with the quieter, more sensitive Merlin usually in darker, earthier colors while Arthur usually wears brighter, flashier clothing. Somewhat justified as Arthur is a prince and would wear fancier clothing.
Teen Wolf: Scott and Stiles fit this trope to a T, with Scott as the Red Oni and Stiles as the Blue Oni. Scott is more impulsive, passionate and reckless; these traits were magnified after he became a werewolf. Stiles is the Blue Oni; he is more logical, calm and composed and doesn't get as emotional and hot headed as Scott.
The Vampire Diaries has a rather unusual example with the brothers Stefan and Damon, with the younger brother Stefan playing a heroic Blue to his older brother's Red. Damon is impulsive and passionate and tends to flip between anti-hero and villain on a whim, while Stefan is usually measured and controlled.
In the early seasons of Farscape, D'argo and Zhaan have this relationship, down to the colors. It's played with, though, as both also have Hidden Depths. D'argo, at heart, wanted nothing more than a simple farm life with his family, while Zhaan's cool exterior hides a seething rage that is terrifying to witness when it breaks through.
Then when Chiana came along and hooked up with D'Argo, she was definitely the red to D'Argo's blue.
Aeryn was the blue to Crichton's red.
John Crichton and Scorpius can also fall under this heading, particularly when they're forced to team up: Crichton is outgoing, exuberant, and (especially in the later seasons) more than just a bit crazy, while Scorpius is cold, calculating, manipulative, and ruthless. Once again, both have hidden depths: for all his eccentricities, Crichton is still a scientist, and by the end of the series, he's developed a knack for planning ahead and adjusting said plans at speed; Scorpius, on the other hand, hides a vicious temper under his reserved exterior.
Blue Bloods: Henry and Danny are red onis; Frank, Erin, and Jamie are blue onis.
Babylon 5: Bester was definitely cool and calculating blue to Garibaldi's indignant and angry red in their ongoing conflict.
Torchwood currently has emotional, impulsive Gwen Cooper and cool, almost perpetually blasé Captain Jack Harkness. In past seasons, hotheaded, profane Owen Harper and reserved, polite Ianto Jones played Red and Blue respectively when interacting with pretty much anyone else.
Frasier (red) and his younger brother Niles (blue). Note that this does not mean Niles is any less neurotic or eccentric than Frasier, just that he has a far milder temper. Their demeanors fit the mold (Frasier's brand of conceited pompousness is overbearing and Hot-Blooded while Niles' is fussy and sharp-tongued) and Niles is more down-to-earth by comparison whenever Frasier gets caught up in his ridiculously over-emotional trains of thought, irrational schemes and obsessions, and explosions of anger or vengeance.
The Nanny: Fran Fine (appropriately called "The Lady in Red" in the theme song) and Maxwell Sheffield.
Psych: Impulsive, intuitive Shawn (red) and thoughtful, cautious Gus (blue).
Breaking Bad plays around with this. For starters, Jesse Pinkman and Walt White epitomize recklessness (youth) vs. calculation (experience). Hank and Walt similarly reflect this, mainly with the former's direct, almost obnoxious way of dealing with his family and job. However, Jesse plays Blue when dealing with his less smart cohorts Badger and Skinny Pete. Walt and Gus Fring also flip this around: the first acts more out of emotion and concern for his family and (sometimes) Jesse. The latter, who has no emotional attachments the audience knows of (or at least living ones), conducts business the way only a cold-blooded monster would, taking extreme caution to keep his respectable businessman facade while not minding his underlings' (or anyone else's) deaths to keep his drug distribution outfit operating.
America's Next Top Model, full stop. At least one model per cycle borders on absolute Red; at least one other borders on absolute Blue; and everyone else falls in between, depending on whom they're compared to.
Their father Dan is the Jerkass red while their Cool Uncle Keith is the obvious blue.
The red and blue universes from Fringe. The people from the red universe are Darker and Edgier compared to their counterparts from the blue universe, who are the main characters of the series. The Bishops tend to be an exception in many ways, which makes particular sense in Peter's case since he's originally from the red universe anyway.
Ultraman Gaia has Takayama Gamu (Gaia, red Ultraman) an idealist who believes that the Gaia's purpose is to save Earth and humanity. And Fujimiya Hiroya (Agul, blue Ultraman), who is more focus on defeating monsters and more interested in protecting just the planet itself, even at the expense of humanity. Fujimiya eventually Tooka Level In Kindness, but remains as more cool head.
In Modern Family, it's astoundingly able to pull off a Red Oni, Blue Oni dynamic with pretty much any pair-up between the three main families. Within the parents there are Claire and Phil, Gloria and Jay, and Cameron and Mitchell. With the kids, Haley and Alex along with Luke and Manny. The pairs and even roles get switched around constantly.
The Inspector Lynley Mysteries: Barbara Havers is red, Thomas Lynley is blue. However, as is this show's habit, the reality is slightly more complex: Havers is certainly more fiery and hotheaded in daily life, but she is generally the cool, collected one in a crisis, whereas Lynley is usually the more rational and pragmatic one, but tends to panic when the shit hits the fan. Also, Lynley is more likely to fly off the handle at suspects, whereas Havers is more likely to react with Tranquil Fury.
Austin & Ally, impulsive Austin (red), and level-headed Ally (blue).
In Bones, the entire character dynamic is based off of Bones being everyone's Blue Oni. The most obvious Red is Agent Booth, though Angela also fits the description rather well.
Lois and Hal in Malcolm in the Middle go both ways in different aspects: Red Lois (temperamental, loud, scary, flying off the handle at the kids) vs. Blue Hal (easygoing Dad, the quiet one); and Blue Lois (more pragmatic, down to Earth, runs a tight ship) vs. Red Hal (impulsive, can be irresponsible). In the balance Lois is overall red and Hal is overall blue though.
Jackie is red to Donna's blue; Kelso is also red to Eric's blue. Donna and Eric were one time snarkily nicknamed "Mom and Dad" among the group by Kelso.
Hyde's bluer than all of them though. Jackie was slightly the blue one to Kelso's red when they were a couple, both being fairly red in general though; the red Jackie/blue Hyde contrast was striking when those two became a couple.
Donna is mostly blue, but she also has some red qualities, as she can be hot-tempered and want to break rules and traditions. Hyde is also rebellious, despite being mostly blue, while Kelso and Jackie aren't, despite being mostly red.
Red and Kitty could go either way with each other: red Red (temperamental, is gonna put a foot in someone's ass) vs. blue Kitty (generally a calming force and more easygoing, particularly with Eric); but also red Kitty (can get sloppy drunk and silly, sometimes snaps and loses temper herself) vs. blue Red ("calm down Kitty", "you've had enough Kitty"). Probably made them a good stable married couple, as they could play either to balance out the other that way as needed. Red could also be quite a Deadpan Snarker and occasionally a softspoken badass (watch out then), both generally blue traits.
Bob was definitely red (impulsive, outgoing, loud) to Midge's calm and cool blue.
In the first season, there is Andy Trudeau (red) and Daryl Morris (blue).
An unusual example in Agents of S.H.I.E.L.D. with FitzSimmons. While Simmons is generally the blue to Fitz's red, they each display some specific traits associated with the other. For example, Simmons shows a reddish tendency towards adventurousness and excitability when confronted with the unknown, while Fitz has the contrasting bluish qualities of cautiousness and anxiety under the same circumstances.
Roseanne: Becky and Mark were red; Darlene and David were rebellious, but were still mostly blue.
Step by Step: The rebellious tomboy Al and the ditzy girly-girl Karen are two different kinds of red; the intellectual feminist Dana is blue.
Rome: Pullo is red, Vorenus is blue. Occasionally subverted, particularly when things go bad for Vorenus
Power: James and Tommy run a major drug gang in New York. James is calm, collected, and business minded, running the night club they use to launder their money. Tommy is impulsive and Hot-Blooded, and primarily handles running their street crews.
Community: Jeff and Annie are this throughout the series. Annie is red whilst Jeff is blue, and this is even highlighted by the colours they wear in the Season 3 episode Digital Estate Planning.
The Man From UNCLE has casually debonair American agent Napoleon Solo as Red Oni to his coolly intellectual Russian partner, Illya Kuryakin's Blue Oni. Slightly ironic in terms of political "colours" of the day, as Kuryakin was apparently a Soviet national living in America and hence considered a "Red" during the Cold War of the 1960's.
Jessica Jones (2015): Jessica is the brash and short-tempered Red Oni to both Luke's and Trish's calmer and more even-tempered Blue Onis.
The two popular talk shows The Jerry Springer Show and The Jeremy Kyle Show definitely serve this trope well. (Red) Jerry Springer's audiences (and guests) are untamed and free to express opinion regardless of the consequences. While (Blue) Jeremy Kyle's talk show is strict, considerate and casts judgement with sincere shunning and less physical abuse.
The Goldbergs: The Goldberg Family served as the loud-mouthed and dysfunctional, Red Oni's to the soft-spoken and well-behaved Kremp Family who were the Blue Oni's.