Basically, I'm going to name every idol that I can think of. I'll list them by their respective groups, and I will not count those whose groups I'm not sure of. I'm really curious how many of them I know lol. I'll count every idol, even those who are no longer active. If I'm not sure what exactly that idol's name is, I won't count him/her.

Seo Taiji & Boys - YG, Seo Taiji

Turbo - Kim Jongkook

H.O.T. - Tony, Kangta, Moon Heejun

Sechskies - Eun Jiwon

Fin.K.L - Lee Hyori

S.E.S - Eugene

Chakra - Hwangbo

DBSK - Yunho, Max Changmin, Jaejoong, Yoonchun, Junsu

Super Junior - Leeteuk, Eunhyuk, Shindong, Siwon, Donghae, Ryeowook, Yesung, Kyuhyun, Kibum, Heechul

SS501 - Hyunjoong, Youngsaeng, Kyujong, Jungmin, Hyungjun

Big Bang - G Dragon, TOP, Taeyang, Daesung, Seungri

BEG - Narsha, Ga In, Jea, Miryo

SNSD - Taeyeon, Jessica, Tiffany, Seohyun, Sunny, Yuri, Sooyoung, Yoona, Hyoyeon

Wonder Girls - Sun, Sohee, SYubin - probably a typo lol.

KARA - Gyuri, Seungyeon, Hara, Nicole, Jiyoung

SHINee - Jonghyun, Key, Onew, Taemin, Minho

2PM - Jay Park, Nickhun, Taecyeon, Wooyoung

2AM - Jokwon, Seulong, Changmin, Jinwoon

U-Kiss - Soohyun, Kevin, AJ, Kiseop, Eli, Hoon, Dongho, Alexander, Kibum

FT Island - Hongki, Seunghyun

2NE1 - Minzy, CL, Park Bom, Sandara

After School - Nana, Lizzy, Kahi, UEE

4 Minute - Hyuna

Secret - Seonhwa

T-ARA - Hyomin, Hwayoung, Eunji Eunjung! This is the after-effect of too much Reply 1997..., Jiyeon

F(x) - Luna, Victoria, Krystal, Sulli, Amber

Rainbow - Jaekyung

ZE:A - Kwanghee, Siwan, Hyungsik, Dongjoon

B2ST - Yoseob, Doojun, Kikwang

MBLAQ - Lee Joon, Mir, Thunder, GO

Miss A - Suzy

DMTN - Daniel

Sistar - Hyorin, Bora

INFINITE - Sunggyu, Dongwoo, Woohyun, Hoya, Sungyeol, Myungsoo, Sungjong

CN Blue - Yonghwa, Jonghyun, Minhyuk, Jungshin

Teen Top - Ricky, Niel, CAP

B1A4 - Baro, Himchan Sandeul was who I was thinking of, but wrote a wrong name lol, CNU

Boyfriend - Youngmin, Kwangmin, Jungmin

A Pink - Eunji, Naeun

BAP - Youngguk It's spelled correctly Yongguk (용국, not 영국 TT.TT), Himchan goes here~

EXO - Suho, Chanyeol, Baekhyun, DO, Kai, Sehun, Xiumin, Kris, Lay, Luhan, Chen, Tao

BTOB - Eunkwang, Ilhoon, Minhyuk

VIXX - N

Tasty - Soryong, Daeryong

Tiny G - Dohee

GOT7 - Jr, JB

So, apparently, I know 159 160 idols by name and group. I know a bunch more, but I either don't really know their name or what group they're in. And there might be some typos (I was glad I even finished it with just one hand), so do correct me if you find something funny ^_^