I definitely missed a few songs especially further down the list. Also while I was going through the weekly charts there were several songs from TV programs (mainly music audition programs from 2010 - 2012) that went to #1 then dropped very quickly off the charts, I didn't include any of them.
Biggest drops from #1 on Circle (Gaon) Digital Chart:
NCT 127 - Be There For Me (-99) (2023)
NCT Dream - Beatbox (-23) (2022)
NCT 127 - Ay-Yo (-20) (2023)
Kang Daniel - Antidote (-18) (2021)
SNSD-TTS - Twinkle (-17) (2012) (After its 2nd weeks at #1, this song has a weird chart run: 1-3-5-8-1-18, does anyone know why it rose up to #1 again in its 5th week?) (BigBang & Wonder Girls album bombs, it would be #8 without the new releases)
EXO - December, 2014 (The Winter's Tale) (-16) (2014)
Epik High - Happen Ending (-15) (2014) (MC Mong album bomb)
SEVENTEEN - Maestro (-15) (2024)
NCT Dream - Hot Sauce (-13) (2021)
iKON - 지못미 (Apology) (-12) (2015)
Turbo - 다시 (Again) (feat. Yu Jae Seok) (-12) (2015)
Trouble Maker - 내일은 없어 (Now) (-11) (2013) (Infinite Challenge album bomb)
SoYou & Mad Clown - 착해 빠졌어 (Stupid In Love) (-10) (2013) (Busker Busker album bomb)
SEVENTEEN - 음악의 신 (God of Music) (-10) (2023)
4minute - 오늘 뭐해 (Watcha Doin' Today?) (-9) (2014)
Beast - 이젠 아니야 (No More) (-9) (2014)
AKMU - 시간과 낙엽 (Time and Fallen Leaves) (-9) (2014) (Epik High album bomb)
SNSD - The Boys (-8) (2011) (after 2 weeks at #1)
2NE1 - 내가 제일 잘 나가 (I Am The Best) (-8) (2011) (Infinite Challenge album bomb)
CNBLUE - Hey You (-8) (2012) (Busker Busker album bomb)
Busker Busker - 처음엔 사랑이란게 (Love, at first) (-8) (2013) (IU album bomb)
HIGH4 & IU - 봄 사랑 벚꽃 말고 (Not Spring, Love or Cherry Blossoms) (-8) (2014) (It went to #1 in its 4th week: 2-3-2-1-9, it was initially blocked by AKMU's '200%' and 15&'s 'Can't Hide It') (EXO album bomb)
Park Hyo Shin - 야생화 (Wild Flower) (-7) (2014) (AKMU album bomb)
Park Hyo Shin - 겨울소리 (Sound of Winter) (-7) (2018)
Biggest drops for other notable artists:
BigBang - 에라 모르겠다 (FXXK IT) (-7) (2016) (after 3 weeks at #1)
SHINee - Sherlock (Clue + Note) (-6) (2012)
Jonghyun - Lonely (feat. Taeyeon) (-5) (2017)
IU - 겨울잠 (Winter Sleep) (-5) (2022) (this is her biggest drop for a solo song)
Lim Young Woong - 우리들의 블루스 (Our Blues, Our Life) (-5) (2022) & 모래 알갱이 (Grain of Sand) (-5) (2023)
Davichi - 안녕이라고 말하지마 (Don't Say Goodbye) (-4) (2011) (after 3 weeks at #1) & 녹는 중 (Be Warmed) (feat. Verbal Jint) (-4) (2013)
Mamamoo - 넌 is 뭔들 (You're the best) (-4) (2016)
BOL4 & Twenty Years of Age - 남이 될 수 있을까 (We loved) (-4) (2017)
BTS - 피 땀 눈물 (Blood Sweat & Tears) (-3) (2016) & Butter (-3) (2022) (after 5 weeks at #1)
Impressively, Twice and Sistar who each have 9 #1s have never dropped out of the top3, and Taeyeon who has 6 #1s where she is credited as the main artist has also never dropped out of the top3 with any of these singles.
Blackpink's 3 #1s have either dropped to #2 (D4 in its 5th week after 3 at #1) or to #3 (Whistle after 2 weeks at #1 & HYLT in its 5th week after 3 at #1). Gfriend's 2 #1s (Rough and Navillera) both only dropped to #2, both after 2 weeks at #1. Red Velvet's 2 #1s both also only dropped to #2 in their 2nd week (Red Flavor) and 3rd week (Power Up after 2 weeks at #1).
No 4th or 5th gen gg who have a #1 (IVE, (G)I-DLE, Newjeans, Lesserafim, aespa and Illit) have dropped out of the top3, in fact, the majority of their #1 singles only fall to #2 after multiple weeks at #1 and then spend several months in the top10, a direct effect of the streaming era.
Singles that dropped to #2: Tomboy (2), Attention (2), After Like (4), Nxde (2), Ditto (13), Kitsch (3), I AM (6), Queencard (5), Perfect Night (6), Fate (3), Supernova (5 weeks at #1 so far, will probably drop to #2 next week)
Singles that dropped to #3: Love Dive (4), Super Shy (8), Baddie (3), Magnetic (3)
Since album bombs are extremely rare these days, it seems that the only artists that will suffer huge drops from now on will be bgs (or soloists with sizable fandoms but limited gp appeal) whose singles reach #1 through mass-downloads in the first week but don't have enough streams to keep the song stable in the following weeks.
