Park Min Young. She isn't on your list, but it's still an answer right ? ^^ Park+Min+Young+pictorial+(1).gif
Yoon Eun Hye and Kim So Eun

They had innocent smile I thought.
Shin Min ah has the best smile! her cute dimples awww :)
IU is so adorable when she smiles/laughs :3
park min young and shinhye
Moon Chae Won and Kim So Yeon
PARK BO YOUNG , her smile kills me every time
Shin Min ah and Park Bo Young ~~ 
Moon Chae Won and Park Bo Young :) ~
Honey Lee that uneven dimple~

And Lee Yo Won
Park Bo Young, she is so cute she looks like a lil puppy. 
Shin Min Ah, those dimples!!!!
Park Min Young, everything she does is pretty...
Jung Eunji, that eye smile, so cute!!
Definitely jumping on the IU and Jung Eunji train. Those two have gorgeous smiles!
Park Bo Young
Gong Hyo Jin
IU

(not in any particular order)
Moon Chae Won (beautiful warm smile)
Jung Ryeo Won (dimples!!)
Yoon Eun Hye (bunny teeth!!)
Han Ye Seul (elegant as a princess smile)
So Yi Hyun (brighten your day smile)
Choi Soo Young (adorable smile)