In 2018, Korean artists pushed the boundaries of what K-pop can do on the world stage. BTS led the charge, sweeping awards, chart victories and records at a constant rate.

Outside of record-breaking victories, 2018 was full of boundary-pushing releases from across the board. Elements of disparate genres -- ranging from jazz to arena rock to ‘80s synth-pop -- snuck their way into our top songs list. While K-pop has always been sonically amorphous, we saw plenty of Korean acts expand their sound while achieving commercial success.

We tend to stick with singles on year-end lists at Billboard, unless there’s a standout deeper cut that we like more -- though we decided to allow two BTS entries on the list this year because, frankly, it was hard to choose between our two nominated songs. This top 20 list is a compilation of the greatest K-pop songs from a year marked by loss, new beginnings and stratospheric accomplishments.

20. Seventeen, "Oh My!" (You Make My Day)

The year 2017 may have been their namesake year, but 2018 was also undeniably good to Seventeen. From the emotional EDM of "Thanks" to the bouncy soundtrack cut "A-Teen," the 13-member boy band delivered their usual range of genre-spanning singles -- the shiniest gem of the bunch coming with their summer release "Oh My!" Incorporating unexpected elements of 8-bit, synth-funk and acappella music, the guys proved their musical creativity is as innovative as ever. -- JEFF BENJAMIN

19. NCT U, "Baby Don't Stop" (NCT 2018 Empathy)

After its opening moments, with a thumping bass line and squelching synths, “Baby Don’t Stop” quickly turns into a sultry pop duet that’s a bit gritty and a bit groovy. Featuring NCT powerhouses Ten and Taeyong, the song thrives on the latter’s taunting, gruff whisper raps, which are littered throughout the pair’s smooth, sensuous verses. Released as part of the amalgamate NCT 2018 Empathy album under the auspices of transformative NCT team NCT U, “Baby Don’t Stop” serves as a prime example of how SM Entertainment’s latest boy b(r)and is pushing the boundaries of what K-pop means in 2018. -- TAMAR HERMAN

18. EXO, “Tempo" (Don’t Mess Up My Tempo)

Cars aren’t the only thing EXO will have racing. The song's meandering pace cheekily contradicts its “don’t mess up my tempo” hook. This bit-sized odyssey puts the pedal to the medal on the chorus before stomping the brakes at the bridge. Then there are the unconventional sounds, which include bed squeaks, pitch-shifted vocals and a funky bassline. EXO also happens to have one of the strongest vocal lines in K-pop -- it’s hard to imagine any other group launching into an a cappella breakdown like this. There are so many twists and U-turns in the song structure that “Tempo” will never swerve off our playlist. -- CAITLIN KELLEY

17. fromis_9, “Love Bomb” (From.9)

Not all cute concepts are created equal. They can be full-on saccharine or include a dose of creepy -- but “Love Bomb” just happens to go hard. A wall of synth bass lines the chorus, which is equal parts powerful and retro, like it was air dropped out of a bubblegum smash from the ‘80s. With a killer flair of modulation at the end, it goes out with a bang. Although the song never made it to Korea’s Gaon charts, it became a cult hit among international fans who learned to love the “Love Bomb.” -- C.K.

16. Loco & Hwasa, "Don't" (The Hyena on the Keyboard, Pt. 4)

A rich and moody R&B duet between the MAMAMOO songstress and AOMG rapper, the two spend the entire song holding off on drinking together in fear of their primal instincts coming out. Not only do the duo lyrically teeter on the verge of giving in to seduction, but their entire delivery feels like they are edging into more vicious vocal and rap sections. They hold off just long enough to make it to the end of the four-minute track. -- J.B.

15. BTS, “134340” (Love Yourself: Tear)

Tear proved that BTS has not reached the final frontier of their sonic development. Flanked on the track list by emo rap and Latin pop, “134340” is a hip-hop approximation of jazz. But the lyricism dwarfs every other aspect of the song -- the former planet Pluto is an extended metaphor for on-and-off relationships. The gravitational push-and-pull of a soured romance turns overlapping orbits into a disintegration loop. In this galaxy, love is far, far away. -- C.K.

14. CLC, "Black Dress" (Black Dress)

A versatile girl group from Cube Entertainment, CLC grew into their own with this single’s hypnotic, shimmying synth melody and dynamic beats, and rapidly became a fan favorite. Throughout, the members switch off between deadpan, aggressive raps and taunting, chant-overlaid verses. Chic and confrontational, “Black Dress” is an earworm like few others we heard this year, and it will make any listener run for the first LBD they can find. -- T.H.

13. Dean - “Instagram” (no album)

Amid a seemingly endless cycle of songs about Instagram, Dean threw out the algorithm to expose the interior life behind his aesthetic profile. Samples of background noises, like a cassette player closing, manufacture a lived-in atmosphere. It’s almost like a filter, the way these effects shellac a vintage sheen onto the song -- and in fact, in the music video, the filters bleed together while closing in on him. “Instagram” is about feeling disconnected from a world where everyone is manicuring their lives -- while remaining far too connected to the app itself. -- C.K.

12. MAMAMOO, "Egotistic" (Red Moon)

Continuing to embrace the globally trendy, Latin-influenced sound as originally explored in their "Starry Night" single, the girl group's signature grit is on full display with this powerful punch of a track. The women tell off a self-centered lover over slick Spanish guitar. Their harmonies sound particularly fierce and poignant on a track that not only shows their maturity but continuing musical growth as a quartet. -- J.B.

11. Super Junior, Leslie Grace & Play-N-Skillz, "Lo Siento" (Replay)

The first of what would become several Latin pop-leaning songs this year from legacy K-pop boy band Super Junior, “Lo Siento” made the group the first artist to appear on a Billboard Latin chart, debuting on the Latin Digital Song Sales Chart at No. 13. Leslie Grace and producers Play-N-Skillz join in on the jam, supported by rhythmic strings and confident dembow beats. This trilingual track -- featuring Korean, Spanish and English -- isn’t just a collaboration in name, but a true representation of the diverse music industries all of the artists involved come from. As K-pop moves more actively into global music industries, "Lo Siento" sets the bar high for such artistic partnerships. -- T.H.

10. Sunmi, "Heroine" (Warning)

The second of Sunmi’s three Warning singles, “Heroine” epitomizes the singer's penchant for simultaneously evoking passion and (occasionally tense) intimacy. As if emulating the chaotic emotions that accompany a relationship’s end, “Heroine” surges with energy before pulling back. In the meantime, the song switches between atmospheric synths, tapping beats, and gentle piano melodies, in its lead-up to the chorus’ explosive chirping electro beats and brassy percussion. Though some plagiarism concerns marred its release, “Heroine” is an unapologetic anthem for anyone who has ever come out of heartbreak more confident after putting themselves ahead of their fallen “hero.” -- T.H.

9. IZ*ONE, "La Vie en Rose" (Color*Iz)

This Produce 48 girl group struck (rose) gold on first try with this stunning debut single. From ambient synth work to reverb-heavy strings, "La Vie en Rose" delivered a rare moment for a new K-pop act to make a major impact with a mid-tempo song, as opposed to the typical high-energy banger. The results landed the group a hit single in Korea and Japan, while making them one of the few K-pop girl groups to send their debut song and album to Billboard's world-genre charts. -- J.B.

8. Apink, "I'm So Sick" (One & Six)

Since their start in 2011, Apink became synonymous in the K-pop world with an innocent style of bubblegum pop. But when their July single began with Naeun confessing she’s “so sick of lying,” it felt a bit meta -- as the six-member girl group swapped out their girlish image for something far more compelling. The stylistic swerve served them well, revealing potential for a new facet of Apink’s career, with its airy, tropical house beats, dramatic guitar riffs, and seismic wails creating a platform for the members’ powerful vocals. -- T.H.

7. iKON, "Love Scenario" (Return)

We all deserved the relaxed vibes of iKON’s deceptively simple hit “Love Scenario" in 2018. After 2017 saw the boy band release a pair of bombastic singles -- “Bling Bling” and “B-Day” -- their first song of the year blew into January like a fresh, laid-back breeze. With a simple melody guided by playful piano chords and clacking cowbells, there’s a sense of ease throughout the track as the members reflect on the memories of a failed romance. -- T.H.

6. Heize feat. Gaeko, “Jenga” (Wish & Wind)

In a year marked by anxiety and uncertainty, Heize’s peculiar spin on melancholy feels timely. Picking up where “You, Clouds, Rain” left off, this jazz-trap concoction constructs a moody soundscape with the drizzle of rain in the background. Her idiosyncratic vocal color has the ability to pack intense emotion into a few syllables. The falling lilt of her voice as she sings “somebody help” is filled with the utter despair of helplessness. Heize is a master at formulating new ways of crying in the jazz club. -- C.K.

5. SHINee, “Our Page” (The Story of Light EP. 3)

When Jonghyun passed away last December, vigils popped up all over the world. New Yorkers gathered around the lights of the Christmas tree at Madison Square Park, and broken voices joined together to sing SHINee’s beloved debut song “Replay,” trying to hold onto him a little longer through music.

Rather than mourn from a dark place, the four remaining members penned a hopeful anthem that carries on the legacy of an irreplaceable artist. The swell of their united voices packs an emotional gut punch. “Our voices are flying,” they sing. “We know it’ll reach you wherever you are.” There are no goodbyes here -- Onew’s softly spoken “you did well” is a postscript marked for delivery. -- C.K.

4. IU, "BBIBBI" (no album)

In what could be perceived as one of IU's most personal songs to date -- firing a warning shot to haters and critics with this deceptively sweet and bouncy R&B cut -- the chart-topping singer-songwriter also creates a universal empowerment anthem. "BBIBBI" sees her emphasizing and acknowledging one's worth and personal rights, giving a "yellow C-A-R-D" to those who disrespect and infringe on others' privacy. -- J.B.

3. BTS, "Fake Love" (Love Yourself: Tear)

The centerpiece of BTS's game-changing Love Yourself: Tear album, lead single "Fake Love" brings a shapeshifting production to explore the relatable moment of realizing a misconstrued, misunderstood love. In a complex production style, the track opens with a dissonantly dark chord for wishing what a love could be, before being juxtaposed with warm melodies to describe the personal pain and identity crises that can come from a relationship. No surprise why the general public was immediately captivated by "Fake Love," which made its live debut at the 2018 Billboard Music Awards and earned the septet their first top 10 hit on the Hot 100. -- J.B.

2. Pentagon, “Shine” (Positive)

Pentagon have thrown countless concepts at the wall since 2016. They’ve gone from the hard-hitting “Gorilla” to the modernized rockabilly of “Critical Beauty” and the moody synth-pop of “Like This.” But their songs all failed to make a dent on the charts -- until they landed on this breakout hit.

"Shine" is a quirky-lite anthem that manages to feel sparse (for K-pop standards!) while encompassing a lot of moving parts. The idiosyncrasies of the 10 members’ voices is striking, as they switch from nasal to gruff to classically trained. But the patchwork of personality is the main attraction. “Shine” does have a bittersweet aftertaste -- it became E’Dawn’s last promoted single after he was booted from Cube Entertainment for a dating scandal. But if the similarly light-hearted follow-up single “Naughty Boy” is any indication, it seems Pentagon have found their sound. -- C.K.

1. Red Velvet, "Bad Boy" (The Perfect Red Velvet)

From the start of their career, K-pop girl group Red Velvet has played with the dichotomy of their name, releasing "red"-infused dance-pop singles as well as sleeker "velvet" ones, and carving out a sizable following for themselves and their chameleonic nature. But it wasn't until the release of "Bad Boy" in January that the act truly took ownership of their smoother side after veering away for the majority of their singles. This standout track fleshed out the second half of the act's identity through its lush soundscape and vivid accompanying music video, which positioned the quintet as confident femme fatales.

The brainchild of Grammy winners The Stereotypes, Maxx Song, Whitney Phillips and K-pop behemoth songwriter Yoo Young Jin, the alt R&B smoothness of “Bad Boy” undeniably proved to be the group’s -- and one of the year’s -- most pristine production to date. Following the opening query of, "Who dat, who dat boy?" the song grooves along as it opens up to its titillating trap beats, coyish hums and echoing “ooh”s as they envelope Red Velvet’s layered, harmonious vocals. After the song’s release, it rapidly became a fan favorite, and was eventually remade into an English version. The group has since turned back to their brighter orientation with the summer hit “Power Up” and November’s shriek-fest in the form of sequel “RBB (Really Bad Boy),” but the year undeniably belongs to the sultry perfection of “Bad Boy.”

Only in 2018 could a “Bad Boy” be so good. -- T.H.