The shipping base was mostly divided over Finn x Marceline, Finn x Bubblegum, and Marceline x Bubblegum. Naturally, some fans have asked the question "Why Choose?" With the introduction of Flame Princess and Huntress Wizard, there's new pairings with all of them. Two different time travel stories in the non-canon comic book strongly imply that Finn, Bubblegum, and Marceline actually do all get together, with the Mnemonoid arc being particularly unsubtle about it.
Shipping Bubblegum and Marceline with Fionna has more than a few supporters.
Amphibia generated a surprising amount of this for a Disney cartoon:
Due to the chemistry between protagonist Anne and her also Trapped in Another World friends Sasha and Marcy — which generated rival ships for both — there's been an increasingly visible portion of the fandom holding that all three have feelings for one another and/or should hook up after they reunite (and, admittedly, have reevaluated their group dynamic). More or less Ascended Fanon at the end of the show, as Word of God notes he deliberately wrote the ending so that viewers could read it as any combination between the girls being canon, including all three of them together as a polyamorous relationship. The polyamorous ship (known popularly as "Sashannarcy") is the fandom's most popular pairing on Archive of Our Own as of the end of the series.
Shipping Sprig in a poly relationship with Maddie and Ivy is quite popular thanks to his past Arranged Marriage to and bonds with Maddie, as well as his canon relationship with Ivy.
After "The Core and the King" aired, fans began shipping Andrias in a poly relationship with his old friends Leif and Barrel. The fact that the three are shown to have some parallels to the Sashannarcy ship above helps to fuel it even more.
To a lesser extent, Hop Pop, Grime, and Sylvia being together is another popular polyship in the series due to the increasing popularity of GrimePop alongside Hop Pop's short romance arc with Sylvia.
Bob/Linda/Teddy is fairly popular, considering that Teddy canonically has a crush on Linda and there's hints that he also has a crush on Bob. As Bob and Teddy are both Ambiguously Bi (Bob moreso than Teddy), it's easy enough to justify.
Jimmy Jr./Tina/Zeke is huge due to the canonical relationship between Jimmy Jr. and Tina, the Ho Yay between Jimmy Jr. and Zeke, and the Ship Tease between Tina and Zeke.
The fandom of Bojack Horseman is not particularly given to shipping, but some seem to prefer Mr. Peanutbutter/BoJack/Diane, considering the strong Love Triangle vibe between them in earlier seasons of the show (and beyond).
Castlevania (2017): Seeing Trevor, Sypha, and Alucard become Fire-Forged Friends has lead fans to declare that the trio belongs together more intimately. The popularity of the ship only climbed higher in Season three when Trevor and Sypha got a Relationship Upgrade and Alucard was confirmed to be bisexual.
In the short "Two Chips and a Miss", from Chip 'n Dale, both Chip and Dale are interested in Clarice, and the three of them are often seen together in fanart.
With Chip 'n Dale Rescue Rangers Chip/Gadget/Dale is sometimes put forth as a solution to their love triangle.
Gyrotank's fanfic series at least suggests this for a time, as Gadget realises the depth of her feelings for Chip and Dale after losing them in the first iteration of a "Groundhog Day" Loop in "Tomorrow is for Never", but the idea is ultimately subverted in the later storyline "Offensive Care", when a chain of events during their latest investigation lead to Chip falling for a doctor while leaving Dale free to propose to Gadget.
Code Lyoko has a couple of possibilities. A few are listed below.
Ulrich/Yumi/Odd
Jeremie/Aelita/Odd
Sissi/Odd/Sam (either blond or the original series African heritage)
Marie/Edd/Eddy, Kevin/Edd/Eddy, Nazz/Edd/Eddy, and Kevin/Nazz/Eddy pop up a lot.
Marie/Edd/Kevin, Nazz/Edd/Kevin and Marie/Edd/Nazz exist; not commonly but they exist.
The Funky Phantom has a rare example for Hanna-Barbera. Skip and Augie both display flirtation for April, who plays back with both of them. This is notably different from how antagonistically a potential triangle on Josie and the Pussycats was where Alan and Josie were clearly a couple with Alexandra the Abhorrent Admirer. Throughout the show April has asked them to make up their mind which one is doing her serenading and that it was too nice a day to fight over her attention. Even funnier in one episode April accepts a ride from a character of the week and Skip and Augie are unified in getting their girl back. In another April gets jealous when Skip and Augie gravitate together towards a female character of the week.
In the Gravity Falls fandom, Dipper/Pacifica/Mabel or Dipper/Wendy/Mabel are quite popular.
Riot, Rapture, and Minx are a group of True Companions who tend to be selfish except when it comes to each other. Word of God is that they're all platonic, though Rapture had one line implying she wants Riot. It's commonplace in the fandom to have them in at least a sexual relationship.
It's not hard to find fanfics that pair up Pizzazz, Roxy, and Jetta or have them in a love triangle. Stormer is almost always left out.
Much of the fandom declared their support for Korra/Mako/Bolin. No, the fact that the two boys are siblings didn't even slow them down. After the introduction of the second Love Triangle of Asami/Mako/Korra and the ensuing Ship-to-Ship Combat with the Mako/Korra/Bolin shippers, and the ultimately victorious pairing being Korra and Asami, some simply decided to ship them all as a beautiful love quadrangle, MaKorraBoSami.
Desna/Bolin/Eska popped up almost the instant the twins were introduced. Poor Bolin.
Tenzin's daughter Jinora is also popular with shippers, with Korra/Jinora/Opal being the most frequently seen in H-art communities.
Lilo & Stitch franchise: Lilo/Stitch/Angel has some level of support in the fandom according to this poll on the Lilo & Stitch Amino community. After all, "nobody gets left behind or forgotten", so why should Stitch choose between his best friend and his boojiboo?
The fandom of The Loud House quickly began developing numerous of these ships. The most common ones include:
Ronnie Anne/Lincoln/one or more of the girls from "Dance Dance Resolution". Again, Clyde can be tossed in, especially if Haiku, Lucy's friend who was introduced in the episode, is involved, as Lincoln was at least slightly interested in her.
Lincoln/at least two of the girls he's shown interest in and/or the girls from "Dance Dance Resolution" (for fans who don't ship Ronnie Anne with Lincoln). Once again, Clyde can be added if Haiku is included.
Benny/Luan/Maggie
Luna/Sam/one or more of their bandmates and/or Luna's siblings.
Lori has had some of this as well, since while most people are fine with her being with Bobby, some like to throw in Carol on top of that, to say nothing of throwing in one of Lori's siblings.
Milo Murphy's Law has Milo/Zack/Melissa. Like the Danny/Sam/Tucker example, all three potential pairs it contains are also BroTPs and it neatly solves several possible shipping wars. Milo's canon crush Amanda can be tossed in as can Bradley, who is crushing on Melissa, though the former is more common as Bradley can't stand Milo.
Notable in that the show itself floats one of these. Adrien, Marinette, and Kagami are out for Sweetheart Ice Cream, and André suggests flavor combinations for Adrien/Marinette, Adrien/Kagami, andMarinette/Kagami. Marinette ultimately decides on Adrien/Kagami, but not before asking about blending all three flavors.
Marinette/Adrien/Nino/Alya is also fairly popular, putting the leads together with the Beta Couple of their best friends.
Kim is commonly shipped with both Alix and Max, so naturally Alix/Kim/Max sees a decent amount of fan content. Once Kim started dating Ondine in canon, fans decided to mix her into the dynamic and it actually tends to work pretty well all things considered.
PAW Patrol has a fair amount of trios fans like together, such as Chase/Skye/Marshall, Chase/Marshall/Everest and heaps more.
PJ Masks naturally has the three main heroes shipped in a triad but shipping Amaya/Owlette with both Conner/Catboy and Romeo occurs as well as does shipping Greg/Gekko with both Amaya and Luna Girl.
The Best Friends Squad, Adora, Bow and Glimmer, are often pushed just a little bit closer together than their canonical very close friendship — particularly since Glimmer has had at least a little Ship Tease with both of them.
Their villainous mirror image, the Super Pal Trio (Catra, Scorpia and Entrapta) are not unheard of as a ship.
Do you like Adora and Catra's Foe Romance Subtext but also like Glimmer with one or both of them? Well, then, Glitradora may be for you!
Tweek/Craig/Thomas and Kyle/Stan/Wendy are pretty common.
While they haven't picked up much ground quite yet, Star vs. the Forces of Evil does have Star/Marco/Jackie and Marco/Star/Tom. The former is helped by the fact that while both have a thing for Marco, Star and Jackie are also good friends with each other. The latter is helped by a lot of Ho Yay. Marco/Star/Tom exploded in popularity after the Season 3 finale contained a surprising amount of Threesome Subtext, including a lot of Ho Yay between Marco and Tom, and the usually hot-tempered Tom being calm and accepting of the fact that Marco and Star had kissed a couple of episodes earlier.
Naturally there's lots of Garnet/Pearl/Amethyst, aka Steven's three mothers. Fics set when Rose was still alive usually adds her to the tangle as well. They even have a Fan Nickname of "Polygems".
Due to certain revelations in "Jail Break", any ship involving Garnet is this by default.
Shipping Buck, Jenny, and Sour Cream — the "cool kids" of Beach City — as a threesome is quite common, and one might expect that Lars/Jenny/Buck and Lars/Sadie/Buck exist as well. The funny thing about Lars is that none of these combinations are too far out there.
Lars/[various gems]/Sadie, as of the Stranded arc.
Jasper/Lapis/Peridot is shipped as a sort of villain counterpart to the Crystal Gems' OT3.
Pearl/Rose/Greg, fairly popular among the fandom, is notable for having been acknowledged in the show. When they fight in Mr. Greg Steven reconciles Greg and Pearl by singing a song written, ambiguously, from his mother's perspective, with the line "You both love me and I love both of you." While it could be about his familial love for two of his parental figures, it's easy to read it as hinting that the love triangle that existed during Rose's lifetime might have become this had she not died.
Noah/Cody/Gwen is fairly popular for fans who can't decide which to pick. Sometimes Izzy is thrown in as well for a neat little foursome.
With the growing popularity of Noah/Izzy and the continuing presence of the Noah/Cody fanbase, several fans enjoy using Izzy/Noah/Cody instead, because, lets face it, Izzy would be happy to share.
And rounding out the ones involving Izzy and Noah, there's the potential for Izzy/Noah/Eva. Certainly helped by the three forming an alliance together in the post-Season 1 special, affectionately dubbed "Team E-Scope" by fans (due to Izzy changing her name to Kaleidoscope with E-Scope as a nickname—don't ask).
Thanks to World Tour and The Ridonculous Race popularizing Noah/Owen as a pairing, Noah/Owen/Izzy has now been added to the ranks of threesomes involving Noah and Izzy, especially since Owen/Izzy were already an Official Couple with a bit of a rivalry with the Fan-Preferred Couple of Noah/Izzy.
After Gwen and Courtney became friends in Season 3, at least before "I See London", there was some fan possibility of Courtney/Duncan/Gwen as a threesome. It became a possibility again in All-Stars, at least until "Sundae Muddy Sundae".
Pahkitew Island introduced Jasmine, Shawn, and Samey, and both Jasmine/Shawn and Jasmine/Samey are popular enough with fans to warrant some fans to just go with Jasmine/Shawn/Samey.
Totally Spies!: Sam/Alex/Clover ship. It doesn't help that most of the boys the three are interested in tend to be one-shots, bar their fellow spy Blaine.
Occasionally seen in the Transformers fandom, taking advantage of the fact that Transformers don't exactly have to deal with reproduction. Sentinel/Optimus/Elita-1 is the most common in Transformers: Animated, while pairings including the twins Sideswipe and Sunstreaker (Ratchet, Bluestreak, and Prowl seeming to be three of the top contenders as the Third) in Transformers: Generation 1 manages to hit the OT3, Twincest and Twin Threesome Fantasy buttons. Blitzwing in Animated is his own personalOT3.
Voltron: Legendary Defender has a lot considering how close its main cast quickly becomes and the close bonds they later form with Pidge's older brother Matt. Popular ones include:
Shiro/Keith/Lance
Shiro/Keith/Allura
Shiro/Keith/Pidge
Shiro/Lance/Pidge
Keith/Lance/Pidge
Pidge/Hunk/Shay
Pidge/Hunk/Lance
Shiro/Allura/Matt
Keith/Lance/Matt
All the Paladins plus Allura and Matt. Shay may or may not be included depending on the fan's personal tastes.
Wuya/Chase/Shadow. It's rarely shipped but it exists.
Even rarer but all the monks in a happy poly relationship, both in XC compliant stories and those that ignore its existence. In the former situation, Ping-Pong may or may not get included.
Rogue/Scott/Jean has been seen in at least a few different X-Men: Evolution fanfics.
The very popular Robin/Artemis/Kid Flash relationship, despite Ship-to-Ship Combat between Robin/Artemis and Artemis/Wally. The three wind up being close friends by the beginning of Season 2 with Wally/Artemis as the Official Couple, but Robin and Artemis' interaction came off as unintentionally flirty to some viewers. The trio is often called "Museum Heist" (because you Rob/Wall/Art).
Season 2 saw a lot of OT3 involving Dick Grayson (especially in the tie-in comic), such as Barbara/Nightwing/Zatanna or Rocket/Nightwing/Zatanna. The former gets quite a bit of attention thanks to Barbara's reaction in this page◊. It helps that the series makes clear that is Dick not only still friends with all of his exes, but his exes are still friends with each other. Sometimes, these are incorporated into Dick's otherOT3s.
Note that the YJ fandom does not stop at OT3s; they can go as high as OT7, and nothing is really stopping it from going higher. Examples can be found all over the YJ Anon Meme.
's fanfic series at least suggests this for a time, as Gadget realises the depth of her feelings for Chip and Dale after losing them in the first iteration of a "Groundhog Day" Loop in "Tomorrow is for Never
