* AcclaimedFlop: While Luna's solo debut EP Free Somebody (and the title track of the same name) did not do that well in terms of sales, it is heavily praised by those who have listened to it.
* SugarWiki/AwesomeMusic:
** [[http://youtu.be/9IZczJ0tTOU This video]] of Luna singing "[[Music/{{Evanescence}} Bring Me To Life]]" with TRAX. Considering that her voice is more refined now, if she sang this again, it would be even more amazing.
** Their album ''Pink Tape'' is considered one of the best K-Pop albums ever, certainly the best of the year it was released, and the trend continued with ''Red Light'' as well.
** Sulli's only solo project, ''Goblin''. While only three tracks long, all are sonically unconventional for K-pop, and Sulli's self-written lyrics are at times legitimately profound.
* BrokenBase: [=MeU=]'s don't seem to always agree on who is the visual of f(x). An example of a discussion can go as one person stating that Krystal is the visual only for someone else to 'correct' that person stating that Sulli is the visual. Eventually another person will show up and say Victoria is the visual. Needless to say, there are many [=MeU=]'s who think f(x) has a visual wall and some might even say the whole group consists of visuals.
* CoveredUp: "Hot Summer", originally by German GirlGroup Monrose. At least judging from number of [=YouTube=] views and comments under the original song, that is.
* CultClassic: Their discography has been seen this way since they started their indefinite hiatus in 2016 and [[PosthumousPopularityPotential especially after Sulli's suicide in 2019]]. While they were popular enough during their run to have ''all'' of their full albums be number ones in Korea, Creator/SMEntertainment did not consider them a top priority, so they didn't ''quite'' have the same level of mainstream recognition as more conventional girl groups like Music/GirlsGeneration. Their only headlining tour took place ''after'' Sulli left and only in Korea and Japan. Though their videos don't get a lot of views, their fanbase is still active and their discography is seen as being ahead of its time in light of similarly electronic-focused groups like Music/{{Aespa}} and experimental groups like Music/NMixx debuting amid their hiatus. It also helps that, although they are mainly preoccupied with their own activities, the surviving members have expressed interest in reuniting after all of them left SM.
* MemeticMutation:
** Krystal's [[http://www.asianjunkie.com/2016/01/03/krystal-a-fucking-savage-on-ambers-snapchat-kimchiovertbitch-ftw/ zinger]] to Amber in Snapchat became a meme overnight.
** A picture of a couple kissing in a hotel room, alleged to be Krystal and Kai, circulated. Fans tried to deny that it wasn't them, it was actually a seal and its trainer. The ridiculousness of the statement [[https://pbs.twimg.com/media/CfPKyeqUsAA9OWr.jpg spawned]] [[https://i.imgur.com/jhG2QD1.jpg memes]]. In hindsight, it is now agreed upon that the couple were ''not'' Krystal and Kai, but still... ''a seal and its trainer''.[[note]]Krystal and Kai ''did'' date, however.[[/note]]
* PosthumousPopularityPotential: Creator/{{Sulli}} had her fair share of fans when she was alive, having been praised as having the archetypical maknae persona (despite being technically the second youngest, after Krystal), but she also had a very vocal hatedom that only got worse as she tried to shift to a more adult image as she grew older. The relentlessness of her antis is believed to have been a factor in her taking a hiatus in 2014 that turned into a permanent departure the following year. Following her suicide in 2019, she has been hailed as one of the group's strengths and recognized as a tragic victim of cyberbullying. Tellingly, Sulli was the ''only'' f(x) member to make the [[https://www.allkpop.com/upload/2021/06/content/281204/1624896264-image.png list]] of the 100 most-searched idols in the first half of 2021. She didn't even have her own TV Tropes page until after she died.
* SignatureSong: "Airplane", which is impressive because it's a B-side. "Electric Shock" may also count due to its appearance in the [[https://www.youtube.com/watch?v=7VVERnrVTW8 skit]] they did with Creator/AnnaKendrick for Creator/FunnyOrDie.
* StuckInTheirShadow: Despite being considered the group's best vocalist (and one of the best dancers), Luna is the least popular member of f(x) by a significant margin and is heavily overshadowed by the others. Amber has also suffered this to some extent, but at least has a decent fanbase among international K-Pop fans (especially those in Western countries).
* ViewerGenderConfusion: Amber can be a very convincing {{Bifauxnen}} at times, to the point that even the other members mistook her for a boy at first.
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