Absolutely Fabulous: Patsy and Edina, although given Eddie's epic inability to relate to anyone else and Patsy's... well, there've been a few joking suggestions that the "heterosexual" part of the description might not always have been entirely accurate. Patsy sabotaged at least one of Eddie's potential relationships (Saffy called her on it but couldn't stop her) and it's been implied that she was the main reason both of Eddie's marriages broke down.
The A-Team. Given a Lampshade Hanging when they buy a house as part of a scheme, and the head of the neighborhood watch asks if they're gay. Hannibal has to correct him quickly to keep B.A. from pounding him.
The whole team, but Face and Murdock especially. They run scams together, tease each other constantly, they're almost always together in the background (usually goofing off) and Face even tells Murdock "You were always the one I thought I could count on," during a serious argument.
Band of Brothers: The book describes this as how the company ended up being. Men would form very close-knit groups of two to four people and those groups would in turn form a closer relationship with other small groups leading to a form of this trope by extension. The TV series doesn't call direct attention to it but it's hinted at in almost every episode with different characters (including replacements). Of course, the entire Easy Company could be said to be one very large version of this trope. Donald Malarkey has stated that not a day goes by that he doesn't thank Adolph Hitler for giving him the opportunity to get to know these men (and most other men of the company expressed similar sentiments while being interviewed for the book).
Apollo and Starbuck from the classic show. Aside from almost always being each other's wingman and even playing on the same team at Triad, both warriors appear to be worried about each other often. Starbuck even gives a hint of jealousy when Apollo is to marry Serina in "Lost Planet of the Gods. In "The Living Legend":
Apollo: Hey. It's me, Apollo. Remember? We talk about things.
Starbuck and both of his life partners Boomer and Apollo form a trio of great friends. There's even a secret handshake between the three.
Boomer: We've been in tighter spots.
Starbuck: We have?
Apollo: And we'll get out of this one, too. I promise.
Battlestar Galactica (2003): Tigh and Adama from the re-imagined show. Made abundantly clear by Adama's breakdown over Tigh's revelation that he is a Cylon, though it was obvious before. Saul's own wife even says that William Adama is the one Saul Tigh loves most in the universe.
Howard and Raj are particularly close friends among the main group of good friends. They often have their moments that show them almost as a romantic couple, and half of the episode "The Cornhusker Vortex" is about them being like husband and wife.
Leonard and Sheldon's relationship is an odd mix between best friends, highly dysfunctional and co-dependent life partners, and parent/child. They have been roommates for a really long time and it's often shown as mutually beneficial.
It is clear that Amy wants to see her relationship with Penny this way, too (and even that the 'heterosexual' part might be negotiable). Penny is more standoffish, however. However, later Penny, Bernadette and Amy develop a real friendship.
Black Books: Bernard and Manny appear to be Heterosexual Life Partners perpetually teetering on the verge of divorce, between the bitter arguments and put-downs, the Ho Yay and the living together thing.
Blackadder: Blackadder and Bladrick may be the most extreme example since this relationship has literally gone on for centuries. While Edmund give Balders a lot of abuse, it's apparent he's at least very used to having him around. One idea Richard Curtis had for a fifth series was "Blackadder as a very fed up and corrupt university don, and Baldrick has been his 'scout' for the past forty years, so in effect they've been married for forty years." (However, the back cover of Blackadder: The Whole Damn Dynasty calls Baldrick Blackadder's catamite...)
Boston Legal: Denny Crane and Alan Shore. They discuss their relationship, as well as social opinion of such relationships, frequently. Alan even discussed the English word "love", and how it's a shame that people use it lightly and a further shame that you can't be precise about your meaning, and then firmly applied it to Denny: "I love you." All in a non-sexual way, and yet these two are more intimate than a good number of television married couples. Subverted in the series finale when they get married, making them literal (but not heterosexual) life partners. The two do end a lot of episodes with some pretty heavy duty male bonding moments—sitting on the balcony, drinking Scotch and...well, without more to go on we'll just have to assume that in this case, a cigar (or rather two cigars) is just a cigar.
Boy Meets World: Cory and Shawn are best friends from a young age; their friendship is just as (if not more) important than their girlfriends. In one episode of the sequel Girl Meets World, when Cory is talking about Shawn and Topanga, he says "My favorite person in the world... and my wife."
Brooklyn Nine-Nine: Hitchcock and Scully. Constant companions at work, and outside of work spend seemingly all their time together. Both are very much heterosexual, one married, and one divorced.
Buffy Summers and Willow Rosenberg. It made for a bit of awkwardness when Willow came out as gay, partially because they had grown apart quite a bit during that season and Buffy had no clue until then. It's given shippers more ammunition than every bullet in every war ever.
Angelus and Spike were close friends at one point. When Angelus got a soul and became Angel they didn't see each other much for about a hundred years. Their mutual hatred of each other (and subsequent Ho Yay) was only escalated because they used to be this trope.
Castle: Detectives Kevin Ryan and Javier Esposito from NY PD are super close, to the point where they have the same lottery numbers ("That way we both win and it's not awkward"). Lampshaded in "The Double Down":
Castle:(to Esposito, after Ryan left abruptly) Don't worry, he still loves you.
The Closer: Lts. Provenza and Flynn of the LAPD in this crime drama. In fact, it is not uncommon to hear Chief Johnson bellowing, "Provenza and Flynn!!" when she hears about their wacky hijinx (one of which involved a dead body, Provenza's garage, skybox tickets to a Dodgers game, and Johnson more furious than anyone's seen her), and when they're not assigned to work alone, she virtually always pairs them up. A Season 7 episode reveals that Provenza's four ex-wives consider Flynn to be their Fifth Ranger and invite him to their get-togethers.
Brenda: Now don't get angry. Lieutenants Flynn and Provenza...
Pope: Already angry.
Community: Troy and Abed become best friends in the first season. They bond over their love of all things geeky. They later become roommates. They even get their own segment during the credits at the end of each episode.
Daredevil (2015): Matt Murdock and Foggy Nelson have quickly become friends upon meeting at Columbia Law School, sticking together through internships at Landman & Zack before going into business as Nelson & Murdock.
Emma and Manny who have been best friends since they were four. At one point in high school, Manny lived with Emma and slept in the same bed. And than when they went to college, Emma made sure that they were roommates. Emma ended up marrying Spinner, who was best friends with Jay, who ended up engaged to Manny.
The Master and The Doctor used to be friends before they became enemies. Even then, it's sometimes portrayed as a friendly rivalry, with the Third Doctor noting that he looks forward to their next confrontation at the end of the Master's debut story, and the Master once remarking that "a universe without the Doctor scarcely bears thinking about".
Eleventh Doctor and Craig Owens are close for the two times Craig appears, despite not being a true companion. The Doctor truly cares about him and admitted Craig as one of his best friends. A running gag between them is that people keep thinking they're a gay couple.
Dollhouse: In flashbacks shown, Caroline (the future Echo) and Bennett (Echo's future foil) became fast best friends in college and were heading in the heterosexual-life-partners direction—until a certain bomb went off....
Oswald: So I was drinkin' the other night, and I got to throwin' up and I got to thinkin'... (long, rambling exposition about him wanting to move back in follows) Lewis: Hey. You had me at 'throwin' up'.
ER: Mark Green and Doug Ross. To the point where as Doug prepared to resign in disgrace, he mourned the likely loss of his best friend as much as the possible loss of the love of his life, Carol. Meanwhile, Mark almost tearfully declared, "I love him like a brother, but I can't do this anymore. It's too hard."
Faking It: Karma and Amy are best friends, right up to the point where Amy kisses Karma to "prove" they're lesbians (It Makes Sense in Context), and Amy starts to have... bigger feelings for Karma.
Flight of the Conchords: Bret and Jemaine live together, even sharing a bedroom if not a bed. Jemaine in particular tends to get jealous of Bret's girlfriends, and they will often accompany each other on dates. The lyrics to "Bret You've Got it Goin' On", which is supposedly a platonic attempt to make Bret feel better about his looks, reveal that sometimes when Bret is sleeping Jemaine puts a wig on him and spoons him.
Frasier: Frasier and Niles Crane. Granted, they are brothers, but they are also best friends and constant companions. The fact that they act very much like a married couple gets a Lampshade Hanging more than once. Made all the more clear when Frasier becomes more and more depressed and jealous after Daphne starts living with Niles, who no longer has quite as much time for his brother as he used to, although this is more because Frasier's unreasonably clingy rather than any real distancing. After Niles marries Daphne, he spends as much time with his brother as he does with his wife.
Roz: I need to talk to you. You're not with Frasier are you?
Niles: Why does everyone treat us like we're joined at the hip? I do have coffee with people other than my brother, you know.
Roz: Oh good, because I'm avoiding him.
Niles: Well then talk fast, because he's meeting me in five minutes.
Will and Jazz are a mild version, since Jazz only appears sporadically on the show. However they have their own handshake, they have been compared to a married couple, and they even have a break-up episode.
Although Will was slow to admit it (and he did on occasion), he and his cousin Carlton become best friends after a while, especially in college where they both rarely spend time with anyone else. Although they are very much Vitriolic Best Buds.
Chandler and Joey. Roommates who do everything together, up to and including buying joint furniture and raising their pet chick and duck. Season 2 even has a 'break up' story. While Joey is quite happy when Chandler marries Monica (with whom Joey has a Like Brother and Sister relationship with), he's upset when they announce they're moving away... until Chandler and Monica show him his 'Joey Room' at their house. (Sort of extending it into One True Threesome territory.)
Rachel and Monica count having been friends their whole lives who drifted apart during their college years. They become best friends again during in their mid twenties when Rachel moves in with Monica and Rachel "grows up" with her more practical friend. Unlike Chandler and Joey, they don't stay quite as close after Chandler and Monica get together.
Chandler and Ross were this during their college years. By the time the shows starts, Ross's place has been taken by Joey (though Chandler calls both of them his best friend), but it's clear from the flashbacks they were very close, including making life-long pacts and spending holidays together. By the end of the series, the three guys are more-or-less a Heterosexual Life-Partners unit, with Chandler in the center.
Eddard Stark and Robert Baratheon were like brothers in their youth, being both brought up by Lord Jon Arryn and having fought in wars alongside each other. By the time the series begins, they haven't seen one another in nine years. Robert tells Ned that he chose him as his brother over his actual brothers, and Ned is fiercely loyal to him. In "The Wolf and the Lion", Cersei snarks that she's sorry Robert's "marriage" to Ned Stark didn't work out. This happens when Ned resigns as Hand of the King and says to Robert's face that he will disgrace himself if he assassinates an exiled princess (who is teen-aged and pregnant).
Stannis Baratheon and Davos Seaworth. Davos is Stannis's Number Two and is completely loyal to him, and Davos is one of the few people Stannis likes and trusts.
Jon Snow and Samwell Tarly. They bond as new brothers of the Night's Watch and are able to help each other out. Jon's actor, Kit Harington, claims that Jon would fall apart without Sam.
Deconstructed with foster brothers Robb and Theon. Robb wants this kind of relationship with Theon, based off the one Ned had with Robert in their youth, but Theon ultimately betrays him, which becomes a crucial factor in Robb's death. However, it becomes a sore point for Theon when he realizes that his foster family embraced him more than his actual family, especially his jerkass of a father.
Missandei (former slave, made free by Daenerys) is Daenerys' best friend, and they have a bond that is more than queen and her loyal servant. They discuss their love life and other issues very intimately, and with much more candour and less regal airs than she displays to anyone else.
Wandering former knight Beric Dondarrion and wandering priest Thoros of Myr, two most prominent members of Brotherhood without Banners (Robin-Hood-kind-of-guys who try to help the small folk). It helps that Thoros is responsible for bringing Beric back from the dead six times.
General Hospital: Sonny Corinthos and Jason Morgan. Despite the numerous women in their lives, they will always choose each other. They relationship to each other is the closest one they have.
Gilligan's Island has Gilligan and the Skipper. Granted, it's mixed with Vitriolic Best Buds (at least on the Skipper's end), but they bunk together, work together, stick up for each other, and panic when they believe the other is in danger.
Everyone's favorite Mother/Daughter duo, the Gilmore Girls. Lorelai and Rory are mom and daughter, but they act like best friends almost all the time. Only sometimes Lorelai has to play the mom card. It has a lots to do with the fact that Lorelai is a single mom and had Rory at 16 and chose to be distant from her parents. Each one of them is the most important person in their life for the other.
Lorelai and Sookie. They adore each other, work together at the Independence Inn and share a dream of opening their own inn together, which they do.
Rory Gilmore is best friends with Lane Kim. They were best friends since they were little girls and had a strong relationship at school and high school. Rory is especially important for Lane because she has an overly strict mother. When Rory goes to college, she and Lane grow apart a bit. They never stop being friends, it is just their lives are now different — Rory is at Yale and Lane has her band in Stars Hollow.
At Yale, Rory bonds with her roommate Paris whom she knows from their prep school Chilton. Rory insists they are not best friends, just very good friends, but it's clear they are super close and support each other in many things.
Serena and Blair. The two girls would rather spend their prom with each other than their boyfriends/love interests.
Nate and Chuck play around with this trope. When the show starts they're this trope to a T, Nate even spending most of his nights in Chuck's bedroom (make of that what you will), but once Chuck falls in love with Nate's ex-girlfriend Blair things turn problematic. During seasons two through four they go back and forth between fitting the trope and being on the outs with each other. Their bad phases tend to begin with Chuck doing something bad and then escalate through Nate being a poor friend. However by season five, and for the rest of the series, they're back to fitting this trope to a T. They also spend most of the series (roughly four seasons out of six) living together.
Greek: Ashleigh Howard and Casey Cartwright. This is most explicit in the final season, when they declare each other to be their soulmates and are both visibly horrified at the idea that their friendship might be a "college relationship".
A Patient of the Week and her best friend, who are both runaways from a small religious group, and have pledged to be together "cradle to grave". Too bad one of 'em's dying.
Christina and Meredith have gotten very close in later seasons, declaring each other soul mates and more than once sleeping in the same bed. Along with Mer's husband. Their husbands call them "The Twisted Sisters".
Mark and Callie really count as an example of best friends ever, despite being opposite genders and Callie being bi. She gives birth to Mark's baby and fully intends for him to raise the baby with her and Arizona (whom she later marries), leading to one of the most beautiful family dynamics on the show. And then Mark dies.
Derek and Mark, once they finally move past that whole Mark-slept-with-Derek's-wife thing. Mark even admits later that he came to Seattle to get Derek back, not Addison. He has no other friends (until Callie) and even considers Derek's mother to be his surrogate mother. Not that it stops him from sleeping with Derek's sisters (one for sure and one implies it's actually the reason).
Hannah Montana: Miley and Lilly. So much so that, in the series finale, neither appears fazed by leaving their boyfriends, but can't stand the thought of leaving each other. Their decision of where to go to college was heavily influenced by where the other would go.
Hawaii Five-0: Steve and Danny were initially Vitriolic Best Buds (with Danny in particular constantly complaining about Steve), yet they simply cannot seem to spend enough time together, to the extent that their work and personal lives have no separation at all. Steve is an Honorary Uncle to Danny's daughter Grace. They are both willing to die for (or simply with) each other. Also, they Man Hug regularly and to openly say "I love you" to each other.
Heroes: Hiro and Ando. In one episode, Ando even comments, "That is how we roll." As a reply to something to the effect of, "You guys go to the bathroom together...?" Hiro uses the same words in response to Ando saying, "You came back for me." It helps that he has a thing for Hiro's sister, so they are verging on a family relationship.
In the first and second series, Horatio Hornblower is best friends with his fellow middie/fellow lieutenant Archie Kennedy. Archie is the first person Horatio meets in the Navy and they get really close. Horatio saves Archie's life when Archie's desperate and decides to die in Spanish prison. Archie saves Horatio's life on a mission when he drags him from a bridge that's about to be blown up. Their relationship is deep and they're as tight as if they were family. During "Mutiny" and "Retribution", Hornblower and Kennedy bond with Lt. William Bush and form a Power Trio until Archie is killed.
In the third series, Hornblower's closest friend is Mr Bush. They meet in series two aboard Renown and bond when they struggle together to save the ship commanded by a crazy Captain, and later even more so when they take over the Spanish fort and capture Spanish ships. He agrees to become his First Lieutenant on Hotspur. Mr Bush is Hornblower's closest friend in the book 'verse, but there they're not too close because book Hornblower is more of a "Man Alone".
Matthews and Styles, most prominent lower-deck characters. They just belong together. Complete with their bickering Like an Old Married Couple.
Matthews:(while Styles dangles precariously off the side of the ship) Why is it I can never find you when I need you?
Bunting and Finch in "The Examination for Lieutenant" are close lower-deck sailors though it's addressed only after Finch's death. Bunting doesn't appear in "The Even Chance", in which Finch is a member of Matthews' clique. Their supposed bond feels like an Informed Attribute. We're told that Finch helped Bunting out when the former was first pressed into service. When Finch dies of scurvy, Bunting goes off the rails.
House: Doctors Gregory House and James Wilson. Wilson is House's best (and only) friend. Wilson is more of a people-pleaser. They enjoy playing mind games with one another. In the second and third seasons, the writers make light of the shipping among friends. Definite Ship Tease.
Stacy: What are you hiding? House: I'm gay. [Stacy glares at him] Oh! That's not what you meant. It does explain a lot, though. No girlfriend, always with Wilson, obsession with sneakers...
Ted, Marshall and Barney's friendship often borders Bromance levels. Ted and Marshall have been living together since college, while Barney is very close to both of them, insisting he is Ted's best friend.
Lily and Robin have both declared the other their best friend and clearly stay very good friends in thirty years. Lily is actually Robin's only female friend, since she can't stand other women. Although it's been hinted a lot that Lily has a crush on Robin.
The IT Crowd: Moss and Roy seem like best friends of the geeky variety, even though Roy tries to deny it and Moss seems oblivious when it is mentioned:
Moss: I do like Roy; I'm just not "curious".
Roy: We are not a married couple ... and if anything I'm the husband!
Mac and Dennis. The two live together, work together, spend all their free time together, and check in with each other several times a day to make sure the other is okay. The commentary for "Mac and Dennis Break Up" has the staff (possibly jokingly) talk about the fact that Mac and Dennis are possibly gay and in a pre-sexual romantic relationship that neither is completely conscious of.
Dee: So you dont think that two thirty-year-old men who spend every waking moment together is a little bit pathetic?
Charlie and Frank. Few others would tolerate the squalor they live in together, but more than that they each enthusiastically support each other's weird habits (like sewer scavenging), have their own traditions and games (like Nightcrawlers) and rely on each other to be able to explain their joint weirdness which is pretty much incomphrensible to anyone else, Gang included.
Mac and Charlie have been friends since childhood, making them the longest-lasting friendship on the show. They both met Dennis in high school.
Jackass: Chris Pontius and Steve-O sometimes give off this "best buds" vibe, especially inasmuch as they eventually got their own show together, Wildboyz. Watch the "shark-fishing" skit in the second Jackass movie, when Pontius is helping Steve-O get the fishhook through his cheek. Pontius seems to be having sympathy pains.
Jessica Jones (2015): Jessica and her foster sister/best friend Trish Walker, who's been stated to be the only person Jessica truly loves.
Kaamelott: Perceval and Karadoc in this French show spend so much time with each other, they end up founding their own clan together.
Kamen Rider: Most protagonists and their deuteragnists have this dynamic.
Shinji and Ren are more often at each other's throats than not, but they do have their odd moments together. Especially when Shinji dies.
Kenzaki and Hajime are very vitriolic best friends, and likewise it's hard to deny the depths of their friendship when the former turns himself into a monster so the latter can continue to live among humanity.
Yuuki and Tomoko from Kamen Rider Fourze, though at times Tomoko's reactions come off more like a Stalker with a Crush. In the Fourze Quiz segments included on the DVDs, they tell each other "I love you" a lot, and when they're on the same team they spend most of the short holding hands, semi-snuggling, giggling, and whispering to each other.
Keen Eddie: The professional friendship between Eddie Arlette and Monty Pippin. Mark Valley: "You got to admit, whenever two guys have to spend an awful lot of time together, the question is going to come up. There's always that thing of, 'Oh my God, are we gay?' Like, not physically, but you're enjoying each other's company — you know what I mean? It could be read that way, and we joke about it, but they're just two regular guys hanging out, spending an awful lot of time together."
Life on Mars (2006)/Ashes to Ashes (2008): Ray Carling and Chris Skelton, in season 2 the hints have been flying thick and fast that there might be a little more than that going on with Ray's chronic resentment of Chris's girlfriend (which admittedly got better during the third season—the resentment, though, not the hints). To wit, Alex's letters for the entire team to be opened in the event of her departure; everyone opens theirs right away, and all we hear about Ray's is that it contains the word "repressed." This bit of dialogue from the season 3 finale:
Shaz: Don't panic, Ray. I ain't going to be no gooseberry. Blimey, I'm amazed you two never tied the knot. Chris: It's legal in Holland. Ray: Can we talk about something else like... women, or snooker?
Lost Girl: Kenzi and Bo are a clear example (though Bo isn't heterosexual). They are roommates for most of the show, and very clearly the most important people in each other's lives. Both have put themselves into incredible danger to help the other one out. So much so that it is Kenzi, and not either of Bo's love interests—Lauren or Dyson—who counts as Bo's "heart" when it comes to magic.
Kenzi: No, Dyson; she loves you, yes; she loves Lauren. But you know that it's me. I'm her heart, you know that.
Merlin and Arthur, despite all their insults (especially from Arthur) and bickering, develop a close bond over the years and are always there for each other. Merlin's entire life actually revolves around Arthur, making Arthur a Not Love Interest to Merlin.
Morgana and her servant Guinevere start out as best friends but it sadly doesn't last thanks to Morgana's FaceHeel Turn.
Morgana and her (possibly) half-sister Morgause have an extremely close Villainous Friendship in season 3. They usually call each other "sister".
Midnight Caller: Before Rusty was killed, he and Jack were best friends who could finish each other's sentences.
The Mighty Boosh: Howard Moon and Vince Noir. They work together, live together, go on adventures together, throw satsumas (tangerines) at each other in the snow while wearing only underwear together...Vince is also often mistaken for Howard's girlfriend or wife (since Dude Looks Like a Lady). Lance Dior claims to have heard that Howard is Vince's wife, that he cooks his meals, cuts his hair, and bakes him "little cakes". The relationship remains strictly platonic, despite a few close calls. Once (infamously) in Party, and once in Boosh Live, when Howard's technique with the ladies is described by Vince as a rude invitation to get into his wheelbarrow (he's from Leeds, you see). Howard protests, claiming he was drunk, and Vince laughs, "I know, so was I — I was in the wheelbarrow."
Morecambe and Wise: A legendary British comic double act. Morecambe and Wise were always shown as very close and quarrelling like an old married couple, but were reluctant for years to do their first sharing a bed skit, even though their relationship is clearly platonic. Supposedly they were both immediately brought round to the idea by one of their writers pointing out that Laurel and Hardy shared a bed on film.
The Muppet Show: Muppets Tonight: Pepe the Prawn and Seymour the elephant. They were stage partners and did almost everything together. Though while Pepe went on to star in more muppety stuff, Seymour was put on a bus.
The Nanny: Fran and Val. They've been best friends since kindergarten, spend almost all their free time together and even took each other to prom. In one episode where a Cambodian girl they sponsored in high school comes to town, they almost immediately begin acting like a married couple with a teenage daughter, even going to couples counselling. Val once implied that she occasionally had sexual fantasies about Fran.
"Guilty Pleasure" lampshades this one with Tony and McGee (Ziva provides the lampshades). The two have a falling out (which Ziva describes as a "seven-year itch") during which Tony spends a lot more time working with Phil McCadden, scheduling "hang out time" together after hours and starting to dress the same. But after McCadden dares insult McGee's skills as an agent, Tony backs away and is soon back by McGee's side, refusing to answer McCadden's calls.
Meanwhile, Gibbs and Fornell visit each other's houses with offers of dinner on the pretense of exchanging case information that could have been traded over the phone.
Gibbs and Ducky. They've worked together for years, and Ducky's the only person who gets to call Gibbs "Jethro".
NCIS: Los Angeles: Callan and Sam are best friends, written that way intentionally, even to the point other characters make comments about them being a married couple.
New Girl: Nick and Schmidt. To the point of Schmidt throwing a wedding-like party to celebrate their having been roommates for ten years. At least one guest had to explain to his mother that despite what it sounded like they were not a couple.
Nip/Tuck: Sean and Christian have been best friends and colleagues since college, and Christian is godfather to Sean's children. The show does explore the possibility of Christian having repressed homosexual feelings for Sean when he starts having dreams about them being lovers, but they both conclude it doesn't really mean anything.
NUMB3RS: Colby and David, even displaying jealousy at each other's outside friendships and acting heartbroken when one or the other is removed from the group.
Peep Show: Mark and Jeremy. In the season 5 finale, Sophie is pregnant and it might be either Mark's or Jeremy's. Mark comments on Sophie's increasingly erratic behavior and says that if she continues like that, they can just adopt the baby "like those gay dads".
Finch and Reese. Reese is extremely protective of and has undying loyalty towards Finch while Finch is only ever open and relaxed with Reese.
Reese: Are you there, Finch?
Finch: Always, Mr. Reese.
Before Reese, Finch had Nathan Ingram; the two were close friends for nearly thirty years from college until Ingram's death.
Playing House runs on this trope, as lifelong best friends Maggie and Emma live together and raise Maggie's daughter together.
Popular: Josh and Sugardaddy are close friends. In one episode, Sugardaddy is jealous of all the time Josh spends with his girlfriend.
Psych: Shawn and Gus, who have been best friends since they were six years old and are practically joined at the hip at all times. Gus later feels betrayed when he finds out that his sister had a fling with Shawn. When Shawn proposes to Juliet in the series finale, he even says "Will you marry us?" since Gus will always be a part of their lives.
Pushing Daisies: Emerson and Ned. Not only do they work together on Emerson's PI cases, but in the process of working those cases they come to know each others' deep, dark secrets which ultimately connects them on a personal as well as a professional level.
Quantum Leap: Sam Beckett and Al Calavicci. Al is about the only thing from his time Sam consistently remembers throughout the series, and both of them sacrificed a lot for one another.
Ready or Not: This show ran on Busy and Amanda being best friends and incredibly close. Busy has several older brothers and Amanda is an only child, so they become extremely close and basically grow up together. The finale shows a flashback when they met as small girls, Amanda crying and Busy helping her out.
Although Olaf Petersen only makes a handful of appearances, a strong impression is given that before the accident, he and Lister were Heterosexual Life Partners. Very close friends, same hobbies and lifestyle, both easy-going... Lister apparently has a tattoo that says "I Love Petersen".
Rimmer and Lister could be considered involuntary Heterosexual Life Partners; there's simply no-one else for them to talk to. They live (well, in Rimmer's case, exist) in a mile-long abandoned spaceship, but still sleep in their old crew bunks in the same room. The episode "Blue" plays with this trope: Lister finds himself inexplicably missing Rimmer and keeps reflecting on all the good times they had (most of them at Rimmer's expense). After this culminates in an infamous dream, Kryten takes it upon himself to remind Lister what he really thinks of Rimmer -- that he's a massive jerk.
Revolution Sebastian Monroe and Miles Matheson, who grew up together and call themselves brothers, though it seems that Bass is much more dependent on Miles as several characters mention his Sanity Slippage after Miles leaves him
Rizzoli & Isles: Maura Isles and Jane Rizzoli. Rizzoli gets threatened by a serial killer? Goes to stay with Isles. Isles' friend gets killed? Reaches straight for Rizzoli. Eat together, run together, have drinks together, Fight Crime(!) together, far and away each other's Most Important Person. Isles is the product of a Friendless Background: she has never had a best friend before Rizzoli, and has a worrying tendency of pointing out to any potential Love Interest that they have a dire, undiagnosed medical condition—Rizzoli claims that men either run away from the badge or want to misuse the handcuffs. Some people see Les Yay, others merely intense friendship, but either way, very, very close—and hilariously codependent. They can't seem to do a thing without each other.
Scrubs: J.D. and Turk. They've been friends since college and their friendship is so strong that Carla has said sometimes she's afraid that Turk will leave her for J.D. They're so close that most of the recurring or one shot characters have thought they were a gay couple at least once. When Turk and Carla came back to work after their honeymoon, JD acted like he'd been gone for years. Turk evens gives his new wife a "Can I go play with my friend?" sort of look before running to hug him.
The Sentinel: Jim Ellison and Blair Sandburg; Blair actually moves in with Jim early in the series. How close they are is clearly visible in the scene where Jim tries to revive Blair, who was shot by Jim's Evil Counterpart.
Sesame Street: Bert and Ernie are friends and roommates, and many a joke has been made about this one. Word of God says that Bert & Ernie were originally conceived to be brothers, but the show's creators saw more storyline potential with them as an Odd Couple pairing.
In Shadowhunters, being parabatai is the Shadowhunter version of this: It means that two warriors fight together as one, with their hearts beating in unison. When one dies, the other immediately knows it. Jace claims that it's stronger than any human bond, but Clary counters that she has the same kind of bond with Simon.
Shake It Up!: CeCe and Rocky, who do absolutely everything together, and have the same hopes and dreams. Reinforced by Rocky's refusal to be on the show if CeCe couldn't be on.
Sharpe: Richard Sharpe and Patrick Harper. After brief enmity and beating the crap out of each other, they settle into a friendship that leads them to walk into combat zones for each other after they each leave the army, and the exchange "Are you with me, Patrick?" "Yes, always." There's a strong implication that when Sharpe is should-be-mortally wounded, he only lives because of Harper's determination that he will.
Sherlock: Sherlock and John, in keeping with their historic portrayals, as very much this — especially by the end of the second season. Irene Adler even points out that they're a couple. When John once again claims that he's not gay, Irene simply says it doesn't matter. Sherlock does this in the episode "The Sign of Three" awkwardly admitting admiration towards John in his best man's speech despite the fact it's hilariously bad.
Sonny with a Chance: Nico and Grady, even with their own 'breakup' episode where they try to replace one another with Sonny.
Sports Night: Casey and Dan. Though each has some significant romantic relationships, their most sustained—and sustaining—relationship is with each other. When Dana screws up her relationship with Casey, it's Dan who knows exactly how and why she went wrong. A painful estrangement, based on professional status and hurt feelings, between the two men is resolved during a Passover seder, at which Kasey confesses that the years he has spent working with Dan have been the best of his life, and he wouldn't trade them for anything.
Starsky & Hutch: The title characters. Very much. Both of their actors even refer to the show as a love story between two men.
Kirk, Spock and Bones form a trio best friends, with Captain Kirk being the one closer to Spock and Bones, while Bones and Spock bicker a lot. Kirk and Spock's relationship grows exponentially over the course of the series, while Kirk and Bones were established to have been VERY close from the first episode, with their friendship reaching farther back than Kirk and Spock's. (Their counterparts from the J.J. Abrams movie were set upon by the plot that they must end up like this. Except less slashable, if J.J. has anything to say about it.)
Chekov and Sulu are depicted as close best friends in Star Trek V: The Final Frontier. Oddly, the rest of canon doesn't really show them to be more than friends and colleagues, though their relationship is expanded upon in some of the tie in novels (where for example Chekov is Godfather to Sulu's daughter).
Doctor Bashir and Chief O'Brien spent so much time together on various projects and on hobby activities that O'Brien's wife Keiko complained about it. They have an argument over it where Bashir says he's wildly in love with Ezri (female, now) but he "likes [O'Brien] more", and O'Brien doesn't feel the same. O'Brien may not immediately reciprocate Bashir's feelings in one scene, but there's a scene where the two are discussing an argument O'Brien is having with Keiko, in which O'Brien says something to Bashir like "Why can't she be more like—" and though he breaks off and then ends with "— a man," it's obvious he was going to say "you." It's fairly obvious from the conversation that O'Brien feels the same way, even if he can't admit it to Julian. Which is a hallmark of their relationship.
"People either love you or hate you. I hated you when we first met. But now, well, now I — don't. Really. Now that is from the heart. I really do...not hate you anymore."
Strange as it may sound, there's an element of this to the friendship between Benjamin Sisko and Jadzia Dax. While she's an attractive young woman now, he still relates to her as his older male mentor, to the extent that his nickname for her is "Old Man".
Star Trek: Enterprise: There's Captain Archer and Trip Tucker. Their hearty attitudes were frequently a source of confusion to mess hall companion T'Pol, though even she recognized the loyalty the two had for one another. When Trip's fears about the Xindi attack on Florida were confirmed that his sister was among the casualties the swiftness with which Archer had his buddy's back (Whatever it takes) is simultaneously enthralling and chilling. In addition, Trip develops this relationship with Malcolm Reed, being the only one that Malcolm feels comfortable opening up to.
Android Data and engineer Geordi. Both of these guys bonded over their love of science's gadgets and gizmos, and could busy themselves for hours tinkering and theorizing. Considering that Geordi's firsthand knowledge of human feeling often made Data something of the pupil, it's no surprise that these two are frequently seen together.
Picard and Riker, in a lesser extent. Both would usually hang out during their free time, and it is Riker who become Picard's surrogate father in one episode where Picard and three others were de-aged, implying the closest bond among his crew.
Star Trek: Voyager: In this show, we have Tom Paris and Harry Kim. They play it cool most of the time, but whenever things get rough, it becomes clear how much they mean to each other.
Supernatural: Dean and Sam Winchester, since they've spent most of their lives with each other on the road, Dean having practically raised Sam. They're apparently "soul mates", making them Heterosexual Afterlife Partners as well. The show's creator, Eric Kripke, jokingly referred to Supernatural as "The epic love story of Sam and Dean". In the season 8 finale, Dean tells Sam there isn't anything he would ever put in front of him.
Survivor: Tocantins: Stephen and J.T. were constantly referred to as the "BFF Boys" or borderline boyfriends by fans during their season. J.T. certainly manipulated the emotions of their friendship to his advantage at Final Tribal Council to win himself a unanimous victory, if later interviews and commentary are any indication.
Teachers: Brian and Kurt from this British series are even commented on for acting in a very similar way to a married couple. They rarely have any screen time apart, even when one of them is in a semi-serious relationship. They also share a flat with each other.
Scott and Stiles have been best friends since kindergarten and stay at each other's side through everything, from turning into a werewolf, asking out a girl, being possessed by supernatural creatures or making the lacrosse team. According to the actors, their closeness is partly because they're both missing a parent and depend on each other more because of it. Hilariously the other characters are all too aware of how inseparable they are, and the only effective punishment their parents and teachers have is separating the two of them. They put their lives on the line for each other all the time, one episode has Stiles risking his life to talk Scott out of committing suicide, while Scott's Love Interest is standing right there. The two of them also plan to live together after leaving home, even though they both have serious girlfriends by this point.
Stiles: Scott, you're my best friend and I need you. You're my brother. If you want to do this, you're just gonna have to take me with you.
Jackson and Danny (although Danny is gay, he hasn't the slightest attraction to Jackson and doesn't see him anything more than a close friend) which, somewhat hilariously, annoys Jackson, as he sees himself as being everyone's type.
Danny: I'm supposed to watch you in bed? You remember all the times I told you you're not my type? Jackson: Just do it. Oh, and FYI: I'm everyone's type.
Twin Peaks: Special Agent Dale Cooper and Sheriff Harry S. Truman have a real bromance going on. Despite their very different characters, they are endlessly patient with each other. In fact, they are visibly appreciative of each other's differences. Gazing, tender smiles, nose tweaking—it's all there.
The West Wing: Jed and Leo spend almost all their time together, they have several old married couple-like moments, engage in tiffs and squabbles that never stick, talk excessively and pointlessly, get antsy and downtrodden when separated, etc. They were friends many, many years before Jed became the President of the United States and Leo his Chief of Staff and closest advisor, and therefore their working relationship (which takes up the vast majority of their waking hours) fits their friendship like a glove. There's a rather hilarious moment in one of the season one DVD Extras where Martin Sheen and John Spencer agree that they're the "parents" of the True Companions that is the main cast, but each believe that they're the husband and the other is the wife. (This troper is fairly sure that someone affiliated with the show called Abbey and Leo the President's "wife and mistress" at one point).
Neal Caffrey and Peter Burke, as Neal is a CI under Peter's watch for a four-year term. Peter even says "For the next four years, I own you." Though they start out antagonistic with each other, as the series has carried on, they have shown more and more care for each other. When Peter is kidnapped, Neal turns over a ring that he has saved for his late girlfriend, Kate, as ransom. When Neal is about to flee the country with Kate, Peter finds them and asks Neal to stay. Neal ends up choosing Peter. And then the Big Bad kills Kate because of this.
Neal and Mozzie. Mozzie started out as Neal's mentor when Neal first moved into New York, but this grew into a very close relationship. Despite this, there's much about one another they don't reveal.
Whose Line Is It Anyway?: Colin Mochrie and Ryan Stiles. They've been working on the show together for decades and both of them have admitted on several occasions that the other one is their best friend
The Wild Wild West: James West and Artemus Gordon, who live, work, play, go on double dates and generally do everything together.
The Wire: Avon and Stringer. Friends from childhood, they ran their empire together, and could be counted on to come through for each other despite disagreements; it was almost as if they were married. Of course, a lot of marriages end badly...