- A lot of tertiary and one-shot characters have become incredibly popular with fanfiction writers or in some cases have large fanbases rivaling those of reappearing characters.
Main SeriesThroughout the seasons
- "Craig and those guys", a sometimes friendly sometimes rival gang to the main characters, usually considered by the fandom to consist of Craig Tucker, Clyde Donovan, Token Black, Jimmy Valmer, and Tweek Tweak. Their popularity rivals the Main Four plus Butters easily. One of the most commonly wished things for the show is to get an episode revolving around their group dynamics.
- Randy Marsh: Once intended to be the rather background parent of Stan but due to his behaviour and nonsensical antics he has taken the Spotlight together with the Main Characters.
- The tertiary classmates can have their own fan followings, such as Kevin Stoley (the Star Wars-loving kid) and Dog Poo.
- As noted above a lot of teriary and one-shot characters are popular with fanfiction writers, but perhaps the most baffling is Damien, the son of Satan, who has spoken in exactly one episode and appeared in the background in a few others. Searching for him on fanfiction.net produces five pages of results, or over a hundred stories. He wouldn't be nearly as popular if slash fans hadn't noticed his interaction with Pip, another example of this trope, in the one episode he was in. If you look closely at those fanfiction.net pages, you'll see that nearly all of them are Damien/Pip fanfics. Which is even more baffling, considering that Damien set Pip on fire to earn the respect of the other boys.
- Ze Mole's only appearance in the entire series (aside from an extremely brief one second cameo in "Two Guys Naked in a Hot Tub", where he's seen on Late Night with Conan O'Brien) is in the movie. He appears for roughly 15 minutes in the movie. He is by far one of the most popular subjects in South Park fan-fiction and fan-art.
- Chef's Parents get a lot of love due to their banter and their stories about the Loch Ness Monster. Many were disappointed that they only appeared twice, not even appearing at Chef's funeral.
- Kelly for being Kenny's first girlfriend and the fact she's the first person who actually cared about Kenny dying and even managed to reanimate him.
- Timmy for being a handicapped kid who despite only being able to say his name isn't treated differently by his classmates or other characters. What also boosts his popularity is more emotional depths in some episodes.
- Butter's 'evil' alter-ego Professor Chaos is rather popular, because how ineffectual and hilarious he is at being a villain
- The popularity of the Goth Kids might be because fangirls like to use them as an outlet for their own angst—which is ironic, because that's the kind of attitude the Goth kids are supposed to be a parody of, with them doing it just to stand out and look down on others. The creators seem to have noticed their popularity, as the characters have been appearing more frequently, and even got to star in their own episode. Twice!
- Just like Professor Chaos, Butter's other alter-ego Marjorine is also popular with the fans.
- For a guy who has only appeared in one episode and whose only relationship appears to be with Butters (meaning there shouldn't be much for fanfic writers to actually do with him) Bradley from "Cartman Sucks" has quite a few stories about him getting with Butters.
- Thomas from "Le Petit Tourette" is loved for being a sympathetic and realistic portrayal of Tourette syndrome.
- Mysterion became one almost the moment he showed up. Even after being revealed as Kennynote , he's STILL one of the most talked about characters. In fact, Mysterion, before he was revealed, was such a major thing, that the South Park creators put out a Who Is Mysterion? t-shirt.
- Nathan and Mimsy have a rather large fanbase. Nathan originally appeared as a minor character in a 2004 episode ("Up the Down Steroid"), before having a major role as the antagonist of the episode "Crippled Summer" years later. In this episode, he was presented as a sociopathic but ineffective Evil Counterpart to Jimmy, and was given a lackey named Mimsy who would always inadvertently ruin his schemes to defeat and/or kill Jimmy. Since then, Nathan and Mimsy have become incredibly well-received, and have been appearing more frequently in the show's recent seasons.
- Karen has gained her own massive fanbase ever since her first speaking appearance in "The Poor Kid". Many fans consider her and her relationship with her big brother Kenny to be among one of the show's most adorable and heartwarming elements, so much so that many fans absolutely gushed at her other speaking role and her redesign in "The City Part of Town", which many consider to be to be one of the best parts of the episode.
- Mr. Adams' from the Season Fifteen finale "The Poor Kid" due to being one of the few subversions of Adults Are Useless in the show and being a Nice Guy with a very sympathetic My God, What Have I Done? moment at the end of the episode.
- As far as Kenny's alter-egos go, Princess Kenny is also well-loved for being a perfect parody of Moe in anime and for being adorable in ...her?... own right, inspiring tons of fanart, cosplay, and even a fake trope page for a Princess Kenny series on this wiki, despite only appearing as an anime character for about 2-3 minutes. While his appearance in The Stick of Truth tones down the anime elements, it also makes him into one of the main villains and the Final Boss via a Plot Twist, despite his super-girly princessy getup.
- The old man who keeps yelling at Cartman for trespassing in his garden during the "Black Friday" trilogy was cited by critics and fans as one of the best parts of those three episodes.
- The little chicken McNuggets from "Cock Magic" was universally loved from fans being just an adorable young chicken that plays Magic: The Gathering and was considered the underdog.
- Despite appearing for only the second half of "Safe Space", Reality has amassed a colossal fan base for being the only one to point out how ridiculous safe spaces are and calling out Safe Spacers on how entitled and pathetic they are. Although he's also received a lot of flak for the notion that anti Social Justice Warriors also hide behind their own echo chambers and communities.
- Leslie Meyers due to being a Running Gag character that PC Principal calls out on during school assemblies. she manages to get even more popular with the revelation that she's the Big Bad of Season 19 and proves to be a very effective antagonist without having to resort to shock humor. There are many fan art with Leslie, with many fans shipping her with either Jimmy and/or Kyle, and are hoping that she returns from the dead and given more prominence and depth to her character in future seasons.
- After the events of "Skank Hunt" and "The Damned", Heidi Turner became extremely popular, especially after the latter gave hernote Ship Tease with Eric Cartman himself, and eventually began dating between then and "Wieners Out".
- "The Scoots" gives the unidentified kids in Fortnite costumes. They're not important to the plot, but are quite popular due to the mysteries behind their identities.
- Josh Carter from Season 22's two-part finale, who was mutilated while working in the Amazon fulfillment center and later leads the Amazon strikers while trapped in a box, is quite popular among leftist fans for being a sympathetic leftist character (even quoting Marxist theory on numerous occasions) despite his appearance and the fact he dies in his second episode.
Video GamesSouth Park: The Stick of Truth
- The New Kid, naturally.
- Annie Knitts saw a notable rise in popularity following her appearance in The Stick of Truth. Primarily because she's often shipped with fellow darkhorse, the New Kid.
- The diabetic Scott Malkinson has also gained a decent following, possibly attributing to his more frequent appearances in recent seasons, but he gained even more popularity as his superhero alter-ego "Captain Diabetes".