Obviously, I'm gonna say Siyeon from Dreamcatcher, but honestly, they're all absolutely stunning.
(G)I-DLE: Shuhua, Miyeon and Yuqi
CLC: Seunghee and Seungyeon
AOA: Hyejeong and Seolhyun
Twice: Jeongyeon
Mamamoo: I'll say Moonbyul, but again, kind of all of 'em...
Itzy: Ryujin and Yeji
I don't stan as many girl groups but like
Mamamoo - All of them ugh
SNSD - Taeyeon
Amber Liu
Loona - Jinsoul, Chuu, Heejin, Go Won, Haseul
Red Velvet - Seulgi, Joy, Wendy
Chungha
Sunmi
G Idle - Soyeon, Yuqi, Shuhua
Dreamcatcher - Yoohyeon, Handong
Twice - Nayeon, Dahyun, Mina, Chaeyoung
Exid - Hani
Blackpink - Jisoo
IU
Gugudan - Mina
Gfriend - SinB
There are a lot of female idols that are gorgeous but top five would probably be Tzuyu from Twice, Doyeon from Weki Meki, Jennie from Blackpink, Nana (idk if she still counts as an idol), Jinsoul from Loona and Irene from Red Velvet.
P.S - I am physically incapable of remembering positions, so I took this post as "who's visuals do you love" rather than "which visual members have your favorite visuals." So some of them may not be official visuals. Oh well.
Red Velvet - Joy
NMIXX - Sullyoon
KARA - Goo Hara
G-(I)DLE - Miyeon
Twice - Sana, Tzuyu, Mina
Blackpink - Jisoo
Miss A - Suzy
LOONA - Heejin
I probably forgot so many bc there are simply WAY too many beautiful girls
(not in order)
Winter aespa
Wonyoung ive
Tzuyu twice
Jisoo blackpink
Irene red velvet
Yeonhee rocket punch
Yuna itzy
Yoona snsd
Sullyoon nmixx
Saerom fromis_9
Solar mamamoo
Somin kard (idk if it is co-ed she is one of the girls)