Millions of us now live in the cloud of the K-pop eruption, with bubble-gummy, hi-hat-filled bands including BTS and Blackpink regularly hitting the top of the charts.

Fewer Americans know that K-pop is just one musical genre among many in a country bursting with sounds — trot, indie rock and rap, to name a few. Any one of them could be the next up in the “Hallyu,” or “Korean Wave” that periodically washes across continents, to mix metaphors.

Last month, legions of Korean music fans were buzzing with excitement over a seemingly obscure news release: Billboard, the music-industry bible that publishes global lists of the top hits, will now count streams from one of the most popular music apps in South Korea, Melon.

While Melon has only a fraction of the hundreds of millions of users of Spotify, Apple Music and other apps that dominate Billboard’s charts, it’s a much better holistic representation of the music landscape in South Korea. Some industry watchers see the deal as a sign that the peninsula’s tectonic plates might be shifting again.

“I think Billboard merging with Melon is going to really open up the chances for other K-pop groups as well as other genres of Korean popular music, like trot, ballads, or indie pop to be more exposed in the U.S.,” said Jung-min Mina Lee, a Duke University professor who studies Korean popular music.

Are you ready for the next big sound? Here’s a guide to the lesser-known side of the Korean music scene, while we wait for another eruption.

Let Lim Young Woong introduce you to trot

If all you know about Korean music is K-pop, you should get familiar with trot. It originated during the Japanese occupation of Korea in the 20th century, and combines traditional storytelling methods with Western pop and folk sensibilities. Trot often tells emotional stories in much the same way that American country or folk might.

It might be best exemplified by Lim Young Woong’s song “Nest.”

Lim, 32, has dominated Korean charts since winning the singing competition show “Mr. Trot” in 2020. As of mid-July, he has 15 songs in Melon’s top-100 chart — most of them more than a year old. His most recent single, “Grain of Sand,” has remained in the top 5 on the Melon charts since its release in early June. It’s common for his fans, many of whom are middle-aged women, to mix with younger K-pop fans at annual Korean award shows.

Get into ballads with Lee Mujin

Lee Mujin, 22, specializes in pop and ballads, downtempo tracks bursting with emotional lyrics and punctuated with belted high notes, perfect for karaoke. “Room No. 8,” from his 2022 EP “Room Vol. 1” exemplifies this: mellow, rich and complimented by clean vocals and sparse production.

Younha: Spanning two decades of K-indie

Nicknamed “Oricon Comet” for her success on the Japanese chart Oricon, singer-songwriter Younha, 35, began her career with immense popularity abroad. She has been a mainstay in K-indie and rock in her home country since her debut in the mid-2000s.

Her 2007 hit “Password 486” evokes the sound of the mid-2000s in a storm of pop-punk-styled grainy electric guitar and lyrics about a secret love sung in a powerful chest voice. More recently, her 2022 song “Event Horizon,” which is significantly slower and gentler in production, has held a consistent spot on the Melon charts since its release.

K-rap. You know you want to hear it.

Born out of Black American communities, traditional African storytelling, Caribbean music and work songs from the period of enslavement, rap made its way into the Korean music scene in the 1990s, shortly after the American music industry began its hip-hop feeding frenzy. With the help of a still-new internet and a globalizing economy, acts such as Jay Park and Seo Taiji and the Boys combined American rap with Korean instruments and lyrics that reflected their own lives.

By 2021, Koreans were watching Season 10 of the beloved rap-battle program “Show Me The Money,” which is where the musician BE’O rose to fame.

After his appearance on the show, BE’O spent 2022 awash in a sea of awards for his melodic rap hit “Counting Stars,” featuring the K-rapper Beenzino. He oscillates between rock-inspired singing, such as on “Love Me,” and syncopated rap-singing over old-school hip-hop beats, as on “Rope (Feat. Kwon Jin Ah).” He also frequently collaborates with K-pop stars including Seulgi of the girl group Red Velvet, fellow rapper Zico and the soloist Sunmi. He appeared on the Melon charts with Zico on the song “Complex” in 2022, and most recently, featured on “Summer” with the Korean Canadian rapper Paul Blanco.

Fall in love with K-rock with Jannabi

Fans of American indie rock might feel at home with “For Lovers Who Hesitate,” a string-laden slow jam from the soft-rock band Jannabi that has appeared on the Korean charts since 2019, when it came out on their breakthrough sophomore album, “Legend.” The band’s gauzy melodies often lean on gentle guitar and piano to accent lead singer Choi Jonghoon’s earnest, airy vocals.

Jannabi means monkey in Old Korean — a name chosen because the original members were all born in the year of the monkey, 1992, although the roster has changed over the years. You can see five little monkeys in the opening shot of the music video for “For Lovers Who Hesitate,” about a guy who falls in love with a postal worker.

Let’s cram another metaphor into this article: a petri dish. Any vibrant art scene is going to feature genre blending, and Zia exemplifies that.

A veteran in the Korean music industry, she debuted in 2007 with the glossy, twinkling EP “Voice of Heaven” and has experimented in several Korean genres, including trot, pop and ballads. She has gravitated more toward ballads in recent years, especially after winning awards for her singing in that style. She has released three singles in 2023 that are charting on Melon.

She incorporates traditional Korean vocal techniques into her songs, such as the unique vocal vibrato she uses in her 2023 piano ballad “Love. What is it,” which climaxes with an electric guitar rendition of Johann Pachelbel’s “Canon in D.”

This article has been updated.