From left to the right Koeun, Lami, Heena, Herin
Based on some unconfirmed sources and rumors, the next SM Ent girl group is said to be debuted in 2019. 
Pann OP asks the opinion from its readers, and questions about their future popularity when comparing to Twice!

Koeun 1999
Lami 2003
Heena 2000
Herin 2004
Below are translated K-netizens comments!
  • [+84 -60] God SM is still the top
  • [+71-7] Please don't mention about TWICE...we just don;t know which group would perform better, but since it's SM Ent, the new group is almost certain to do well
  • [+67 -8] The members will be prettier when they get beauty care, there will be more members too
  • [+32 -6] They are SM Ent, they are going to get good concept strong fanbase. I don't think they can beat TWICE. Look at these trainees they aren't impressive. These are the top trainees they have, since it's official.
  • [+28 -1]They are the next main girl group of SM Ent. SM Ent will have collaboration with China's Yuenha Ent and Japan's Avex to debut a group from these three countries. The collaboration debut will have chinese and japanese. Lee So Man talked about this at a recent conference.
  • [+27 -0] SM Ent's main groups members aren't usually less, they prefer in big numbers, DBSK and SHINee are unusual case of hitting big in small number of members.
  • [+21 -2] Koeun and Lami are so beautiful . Lami will be at Yoona's level when she has grown up. There should be another 4~5 members . I guess this girl will join the lineup too. (Below)
SM's Trainee Baek Jeong Yeon