7 Yüz: Sinem, a poised Statuesque Stunner who exudes self-confidence, is a foil to Pınar, the protagonist of "Hayatın Musikisi", who is mousy, introverted, and even physically diminutive.
15/Love: High School Hustler Gary "Squib" Furlong and Dean Bitterman Harold Bates may spend the entire show opposing one another, but at the core of things they're very similar, being a pair of Manipulative Bastards with flexible attitudes towards the rules, no time for stupidity, and an amazing ability to convince others to do things for them. Don't tell Squib, but Bates is exactly what he is going to look like at thirty-five.
24 has Jack Bauer and David Palmer. Both are willing to do whatever it takes to save the world even if it means resorting to questionable means but David has the added ability to mask his true personality behind a face of amiability.
By Season 7, it becomes apparent that Jack and Tony Almeida are these to each other. They start out as relatively stable CTU agents who are wiling to undergo physical and emotional duress to fulfill their duties, with Jack as the one more willing to go rogue and Tony as the quieter, static one. However, as time goes by, it becomes clear that Tony is far more unstable than Jack. Both character lose their wives at some point during the show, but while Jack wallows in self-despair before immersing himself into his work, ultimately putting others before himself, Tony stops at nothing to get back at his wife's killers, gunning down people both guilty and innocent in order to accomplish his goal.
Walter White and Jesse Pinkman. Despite being partners, their character developments have run parallel but in completely separate directions. Originally it appeared that Jesse would be the remorseless criminal to Walt's principled, well-intentioned one. As the series went on, Walt eventually showed himself to be a textbook example of a Sociopath, selfish and egotistical, and even willing to poison a child to save his own skin. Meanwhile Jesse showed himself to be one of the few morally decent people on the show, feeling incredible guilt and self-loathing for the horrible things that he's done while also feeling trapped in the life he's in, which he is clearly not cold enough for.
Examine how Jesse breaks things off with Andrea to protect her, right around the time Skyler becomes basically Walt's prisoner because he refuses to believe he is a danger to her or the kids.
Hank and Walt. Terrible experiences change both men, but while Walt becomes even more consumed by pride and turns into a ruthless criminal, Hank manages to subdue his Good Is Not Nice tendencies, becoming more humble and arguably an even better cop.
... until season 5B, when Hank discovers Walt is Heisenberg and becomes fully obsessed with it, even being called out in the fact that the Heisenberg hunt is his personal obsession.
Skyler and Marie, sisters. Both love their husbands deeply during the beginning of the series, and both of their husbands change during trying circumstances. Between the two, however, Marie stands fast by her husband, supporting him even in his darkest times and her love for him never changing even after he is dead. Skyler, however, becomes cold and distant from her husband, and goes to great lengths to subvert his illegal enterprise, up to and including having an affair.
Jesse and Todd. Both have a lot of respect for Walt and call him Mr. White, but Todd has no problems being Walt's subordinate. Also, contrast Jesse's initial appearance as a mere thug who later turns out to be much kinder than expected with Todd being introduced as a seemingly unassuming nice guy who later wouldn't hesitate to murder a young child. Which in itself is also a stark contrast to Jesse's love of kids. Todd also appears to be a good deal less competent at meth cooking than Jesse, with the quality of meth being churned out sharply dropping as soon as Heisenberg retires and Todd is left to cook alone, in contrast to Jesse who eventually becomes every bit as good at cooking as his mentor.
In the final season, Walt and Gus. After killing Gus, Walt takes his place as the drug kingpin of the American southwest. Both operate civilian businesses to disguise their illegal activities (Gus's fast food joint and Walt's car wash). However, Gus built his empire over several years, is cold and calculating, and also very practical, and remained successful for several years until his death. In comparison, Walt essentially takes his empire after killing him, is impulsive when it comes to the things and people he cares for most (his family, Jesse, and his millions), and is only successful for a few months until his empire comes crumbling down around him.
Walt and Mike. Mike has a considerable amount of money stashed away in his granddaughter's name, making him and Walt two men committing crimes for their families. However, Mike's professionalism and caution allows his work life and home life to remain separate, while Walt's family has become horribly entangled in the meth business. And Mike's emotional stability has allowed him to retain an excellent relationship with his granddaughter and presumably her mother as well, while Walt is emotionally isolated from his family.
Gus and Lydia. Both are consummate business people, who dress perfectly and try to approach the meth trade with a degree of professionalism not normally seen in the "game". However, while Gus was calm, unflinching and relatively reasonable, Lydia is paranoid, unpredictable and unwilling to accept the brutality of the drug world. The contrast is best illustrated in Gus's massacre of the cartel and her disposing of Declan's crew - he moves between bodies without fear while taunting the remains of his enemies, while Lydia plugs her ears not to hear gunshots and later has to literally be guided by hand with her eyes closed through the carnage.
Hank Schrader and Steven Gomez. Gomez was never right once about anything in the entire series, not at least while they were in the same scene. He can't find the meth hidden in Krazy-8's car, but Hank does; he disbelieves in Fring's involvement in meth, but Hank is proven right; early on he dismisses Lydia as a suspect, but Hank noticed her mismatched shoes. Even in the DEA agents' walkthrough of the burned-out superlab, Gomez guesses that a burned-up and molten lump mounted high on a railing, clearly separate from everything else, is "lab equipment." Schrader correctly says "a camera." Makes you wonder why he was considered competent enough to be given the El Paso assignment.
Robin Wood (Buffy the Vampire Slayer) could be considered one to Daniel Holtz, a Big Bad of Angel season 3. Both lost their families to vampires (ironically, the vampires in question are Angel and Spike, respectively) and sought vengeance. Like Holtz, Wood found positively no solace in Spike's ensoulment or remorse and only cared about his revenge. However, Robin eventually managed to let go of his hatred and become a trusted friend and ally to the Scooby Gang, whereas Holtz was single-mindedly consumed by his desire for vengeance to his last breath.
Wesley to Giles. The curmudgeonly Watcher never forgot the grief he suffered under Wesley, as Andrew later reports in Season Five of Angel.
Faith to Buffy, particularly during her FaceHeel Turn in season 3 of Buffy and later on note (Angel season 4, Buffy season 7 and the Season 8/Season 9 comics) with her becoming an Anti-Hero in contrast to Buffy.
Cobra Kai is largely constructed around this type of relationships.
The clearest one is that between Johnny and Danny, who both grew up fatherless and turned to their senseis for guidance, and who both peaked in high school. Johnny is an impoverished degenerate who is trying to become a better person, in spite of being a bit hazy on the actual mechanics of doing so. Danny is a fundamentally decent upper-class man who sees himself as justified in backsliding because of his loathing of Conra Kai and what they stand for... but he isn't always right.
Miguel and Robby are foils to each other. Both are young, directionless men who took to the guidance of their senseis, but where Robby was a bad kid who learned focus from his sensei, Miguel was a good guy who was taught to tap into his anger.
Hawk and Miguel are Cobra Kai's star fighters, but where Miguel retains his moral core, Hawk doesn't.
Sam and Tory. Both are karate fans with romantic interest in Robby and Miguel, but Sam is a Girly Girl who dresses in pastels and raised heels, comes from an upper-class family and trains in the circular, defensive, goju-Ryu-derived Miyagi-do style. Tory, on the other side, is a tomboy from the wrong side of the tracks who prefers black, plaid and flats and trains in the linear, aggressive, Tang Soo Do-based Cobra Kai style.
The Doctor (and to a lesser extent, the Time Lords overall) and the Daleks are mutual Foils of each other. Both are beings who use time travel as a means to get around the universe, have incredibly high standards and mutually have fear and hatred towards one another. What sets them apart (aside from species) is the Daleks are extremely xenophobic and will kill everyone and everything, while the Doctor gives one chance to the Monster of the Week to go elsewhere in the universe and live, or will kill them to save others.
Each Doctor is also a deliberate foil towards their immediate predecessor, and sometimes to ones before that. Some examples, in no particular order:
The Ninth Doctor loathes humanity for its stupidity, the Tenth and Eleventh Doctors love humanity for its specialness.
The Third Doctor came to appreciate his exile on Earth and kept coming back to UNIT even when the TARDIS was restored, where the Fourth Doctor resumed his travels and was content to consider himself a wanderer in eternity.
The Seventh Doctor was a master planner who often manipulated his enemies into destroying themselves in various media, but the Eighth Doctor was a more idealistic hero who became broken and driven by the tragedies he was forced to endure in the course of his lifetime (various media included him losing his memory after facing an invasion of Gallifrey led by his possible future self, being transformed into a being of anti-time and forced to exile himself from his universe, and witnessing his people descend to the level of their enemies during the Time War).
The Meddling Monk to the Doctor, especially the First Doctor. They are both Time Lords who left Gallifrey to explore the Universe. However, when the Doctor first met the Monk, he was adamant about not changing history, while the Monk gleefully interfered with history and tried to make enormous alterations, which the Doctor criticised him for. Amusingly enough, the Second Doctor was put on trial for interference, and the later Doctors are quite lax about interfering history. However the Doctor still tries to keep events on track and not interfere with the most important points, while the Monk's intention is to alter events. This aspect is played up in Big Finish Doctor Who between the Eighth Doctor and the Monk. While the Doctor tries to save people without thinking on a The Needs of the Many scale, the Monk tries to change history for this reason, such as trying to kill thousands of humans to prevent a race of billions being wiped out later. Played further later on, when the Monk joins the Daleks and appears genuinely shocked when they betray him and kill the Doctor's former companion Tamsin.
Captain Cook from the Classic series story "The Greatest Show in the Galaxy" is a one-off contrast with the Seventh Doctor. Much like the Doctor, the Captain is an eccentric explorer who's much smarter than he appears to be. He even has his own companion in the form of Mags. But unlike the Doctor, he's also an amoral coward who's more than willing to sell out others to save his own skin and he treats Mags more like an object than a trusted friend, openly referring to her as a "specimen".
Adam Mitchell from "Dalek" and "The Long Game" is one towards the Doctor's companions, particularly Rose, the main companion in those episodes. He accepts an offer to travel with the Doctor, but whereas the usual companion does it because they want to have adventures, Adam does it because he sees a potential opportunity to enrich himself, which gets him kicked off the TARDIS pretty quickly. He was specifically designed as the kind of person who would make a bad companion.
Adam returns in Prisoners of Time, a miniseries of comic storylines for the fiftieth anniversary, which sees him capture all of the Doctor's companions from various points in his history up until Clara Oswald, believing that the Doctor's companions are little more than pets to him.
Captain Jack Harkness is one towards Nine, especially in his first story, "The Empty Child"/"The Doctor Dances". This is mainly via a Noble Male, Roguish Male pairing, as the ex-Time Agent Jack is working as a con man targeting other time travellers, and accidentally endangers the human race by doing so, while the Doctor has to fix the mess.
"The Girl in the Fireplace": Madame de Pompadour is one to Rose. Reinette is cultured, intelligent and very powerful, despite coming from a society where it wasn't normal for women to be so, and well in control of both of the men in her life, loving the both equally. Rose is from a society that encourages equality but isn't that special, and she can't find a balance between the two men in her life, meaning one always feels left out. Also, they're both blonde.
Lester Nygaard to Emmit Stussy. Both wind up killing a family member in a heat-of-the-moment action: Lester his wife who despised and belittled him, and Emmit his brother who actively tried to ruin his life for a petty feud. The difference is primarily in how both characters cope with the murder, especially post-timeskip. Lester is quick to absolve himself of responsibility and heap the blame on others, and gradually sinks in to depravity and sociopathy, while Emmit is gradually consumed by guilt and regret, culminating in him attempting to stand up to Varga and his organization by confessing to the police.
Also Peggy Blomquist to Lester Nygaard . Both start in a similar place, trapped in relationships they find stifling, Lester to a woman who despises and belittles him and Peggy to a man who loves and supports her. Lester just accepts his lot, but Peggy actively tries to improve her situation and status in life. The difference is most tellingly shown however by their character development in their respective seasons. Lester starts off as a sympathetic character but loses that trait by through his actions throughout the first season, while Peggy starts off unsympathetic but gains audience sympathy as her character develops. Lester killed Pearl and was prepared to abandon Linda while Peggy stands by Ed throughout and at the moment when she's about to go on the run changes her mind and goes back to support him. The single biggest difference though is their actions in the final episodes. Lester sends Linda to her death at the hands of his season's Big Bad to save himself and dies fleeing his just rewards, while Peggy goes to fight her season's Big Bad to defend Ed and ends up living and accepting her punishment.
Sy Feltz is this to Nikki Swango. Both of them serve as The Lancer to Emmit and Ray respectively, but whereas Nikki is the truly dangerous and intelligent one in the relationship (whose only flaw is her tendency to overthink things), Sy is completely incompetent and usually makes things worse for Emmit with his own stupidity.
It's been pointed out that on Firefly, Jayne's character exists largely to show what a true Jerkass and amoral character would actually be doing every time that Mal is trying his best to pretend he's those things.
Friends: Monica Geller and Rachel Green. They grew up together but Monica was The Un-FavouriteFat Best Friend who got nothing but hell from her parents, and Rachel was the Spoiled SweetLovable Alpha Bitch who everyone adored. As adults Monica is the Team Mom of the gang and focused on her goals. Rachel is the baby of the group and totally lost in the real world. Even their romantic lives contrast with Monica settling into a happy relationship with her best friend but having to push through infertility issues and adopt a baby while Rachel has a ten year Can't Stand Them, Can't Live Without Them dance with an unplanned pregnancy in the middle. Their original characters descriptions spell it out nicely:
Monica: "Smart. Cynical. Defended. Had to work for everything she has." Rachel: "Spoiled. Adorable. Terrified. Has worked for nothing of what she has."
Dorothy was born in New York to struggling immigrant parents, had a shotgun wedding at 17, divorced her deadbeat husband, is Hollywood Dateless, and is generally very cynical and progressive.
Blanche, on the other hand, was born in Atlanta to Old Money aristocrats, was head over heels in love with her husband George, Really Gets Around, and is much more optimistic and traditional.
In ''Sesight stands as possible, and believes marriage is A Fate Worse Than Death. Marshall loves committing and being married. Many episodes revolve around Barney egging Ted on to live the single man's life and Marshall encouraging him to commit.
The Lupinrangers are Phantom Thieves whose designations incorporate their respective colors (Lupin Red, Lupin Blue, and Lupin Yellow), wear caped outfits that resemble formal wear with top hats incorporated into their helmet designs, and have black highlights on their suits. The Patrangers, on the other hand, are police officers who have numerical designations (Patren #1, Patren #2, Patren #3), wear outfits that resemble police officer uniforms with shoulder pads and helmets with visors shaped like police hats, and have white highlights on their suits.
The Lupinrangers' VS Vehicles are airplanes, while the Patrangers are patrol cars.
The Lupinrangers' benefactor, Kogure, is a mysterious Japanese man dressed as a butler, is quiet, and occasionally speaks French. The Patrangers' boss, Commissioner Hilltop, is African-American, much more personable, and occasionally speaks in English.
Akari/Lupin Red is easygoing and mild-mannered, while Keiichiro/Patren #1 is one of the most Hot-Blooded Red Rangers in the series's history.
The Lupinrangers' Lancer, Touma/Lupin Blue, is a quiet and thoughtful young man who is passionately committed to his fiancee. On the other hand, the Patrangers' Sakuya/Patren #2 is an excitable Keet and a shameless flirt.
Most protagonists from the Kamen Rider franchise have this relationship with their Deuteragonists. Notable examples include:
Kamen Rider Ryuki: Shinji Kido/Kamen Rider Ryuki and Ren Akiyama/Kamen Rider Knight. Shinji is bright, optimistic, and entirely selfless in his dedication to put the needs of others before himself. Ren is dark, cynical, and entirely selfless in his willingness to throw everything away to save the love of his life.
Kamen Rider Amazons: Both Amazon Riders are this to each other. Jin Takayama/Amazon Alpha is a tough and confident adult while Haruka Mizusawa/Amazon Omega is a frail and sensitive teenager. Also, Jin's apartment is very messy and Haruka's "house" is neat and solitary. This is inverted when the two are in battle however; Jin is collected and in-control, while Haruka acts closer to a wild animal. Then dramatically reversed by the end of the first series: Jin has become a bloodthirsty monster no better than a feral Amazon, and Haruka is the in-control one fighting for a civilized reason.
Kamen Rider Ex-Aid: Emu Hojo/Kamen Rider Ex-Aid, Hiro Kagami/Kamen Rider Brave, and Taiga Hanaya/Kamen Rider Snipe. Emu is a passionate doctor who not only seeks to cure his patients, but to make them happy. By comparison, Hiro is more cold and emotionless and is only interested in curing his patients, nothing more and nothing less. Compared to them, Taiga is more morally ambiguous: a back-alley doctor who is determined to cure the Bugster pandemic by any means necessary, up to and including defeating other Riders and stealing their Gashats.
Mirabelle and Devin in The Kicks: Both are passionate, talented soccer players, but Devin is a kind-hearted and outgoing, while Mirabelle tends to be snarky, apathetic, and downright rude on occasion.
Parker and Sophie seem to have this feel. Sophie is classy, social, and likable, but fake, while Parker is crazy, has No Social Skills and thus is off-putting, but honest (if blunt).
Peggy is also this to Parker as a normal citizen. She is also one of the nicest characters on the show.
In Lost, Jack and John Locke are practically the poster boys for this. Jack's the Man of Science, John Locke's the Man of Faith. But by the end Jack becomes the Man of Faith himself, with John Locke dead and Jack knowing that, if it weren't for him, if he had only believed John Locke, he would've still been alive, he finally begins to believe.
Arthur and Lancelot. Everything from their temperament to their social standing to their hair/eye colour is designed to contrast with the other, as do their relationships with both Merlin and Guinevere. In the last case, even their kisses with Guinevere are shot as stark opposites: Arthur's is a Lip-Lock Sun-Block, whereas Lancelot's takes place in a darkened tunnel.
Also Guinevere and Morgana. At the beginning of the show Gwen was Morgana's haidmaiden and the two of them were close friends, only to be gradually estranged as the show went on, what with Gwen falling in love with Arthur, and Morgana falling to the Dark Side. Essentially, the higher Guinevere ascends, the lower Morgana falls.
From season 10 of Murdoch Mysteries Detective Watts is an equally brilliant detective, but Murdoch's exact opposite in every other respect: slapdash instead of methodical, prone to following tangents instead of procedure, more likely to come up with a philosophical study of the nature of the murder than a scientific explanation of its method, and, at least initially, with a tendency to give up talking to people who can't follow his reasoning as opposed to Murdoch's patience and love of explaining things.
In The Musketeers, Aramis and Rochefort. They are both members of the French court who love the Queen. However while Aramis is loved back by the Queen and fathers her child, Rochefort's love for her is a far more creepy desire, to the point he has a prostitute dress up as her, is only loved by the Queen as a friend. Rochefort finally tries to rape the Queen and have her killed by revealing her affair and framing her for an assassination attempt on the King.
Constance and the Queen. They are both married women who have an affair with a Musketeer, D'artagnan and Aramis respectively. However, while Constance's relationship is more public and her husband's death means she can finally marry D'artagnan, the Queen must keep her relationship secret.
Ninja Turtles: The Next Mutation has this with Donatello and Venus de Milo. Donatello prefers to solving problems the scientific way, while Venus sticks to trusting the mystic arts. Understandably, this causes them to occasionally get into squabbles.
Jonathan Kent and Lionel Luthor to a lesser degree (Ironically, after Jonathan's death, Lionel's contact with the Kents and his temporary role as Jor-El's vessel cause him to become a better person.
Clark and Oliver. It highlights their conflicting idealism and their willingness to act.
Chloe and Oliver start out somewhat similar to the above pair, shown best when Oliver kills Lex. But Oliver says she is Not So Differentwhen it comes to protecting Clark. This, combined with her bearing witness to the fallout of Doomsday, lead to Chloe taking a more hard-boiled approach to fighting crime in Season 9, and she and Oliver cease being foils for each other, and instead jointly become foils against Clark's more idealistic methods of crime-fighting.
Daniel Jackson and Jack O'Neill often serve as foils to each other in Stargate SG-1. (Idealism vs. cynicism, brains vs. brawn (although Jack is not as stupid and Daniel is not as wimpy as they'd like you to think) naivety vs. experience, etc.) This becomes less apparent over the years.
Star Trek: The Next Generation: Aside from getting beaten up to show how tough someone is, Worf's primary role on the show is to suggest a short-sighted, violent or xenophobic course of action so that the rest of the command staff can shoot him down and show off how wise and diplomatic they are.
The spin-off Q Continuum novel trilogy introduces the character of 0, who essentially serves as a foil to Q; they may both 'test' lesser races for their own agenda, but while Starfleet is frustrated by Q's actions, Picard must concede that Q has allowed his human opponents to 'win' on occasion where 0 just changed the rules the second he was about to lose.
The Wire loves this device. There's a lot of parallels between different characters, both those in direct contact with each other (like McNulty and Kima) and some from across different storylines entirely (like D'Angelo Barksdale and Nicky Sobotka). Most conspicuous are the duos of Herc and Carver and Bubbles and Johnny. Herc and Carver are both thuggish and brutal police officers, but Carver shows himself to be more sensitive and thoughtful over time. Johnny is Bubbles's protégé in the streets, but is much more blasé about their predicament and has an "us vs. them" mentality towards the police. Eventually, the underlying differences in both pairs lead the characters in very different directions.
Xena: Warrior Princess: Xena's companion Gabrielle acts as a foil as her compassionate and innocent nature contradicts Xena's bitter and ultra-violent disposition. This dynamic makes up for many of the show's subplots as well as main ones (usually when Xena's foes attempt to separate the duo by showing them the extent of their differences). See The Lancer also.
The X-Files: Dr. Dana Scully is the scientific-minded rational foil to the infamous agent Fox Mulder, widely known within the bureau as Spooky Mulder for his unconventional methods and belief on the paranormal.