4 Elements Mega Project was fully revealed (a while ago).

The Fire (Namneung-Noey)
https://www.youtube.com/watch?v=erOZdx3WALk

The Air (Freen-Becky)
https://www.youtube.com/watch?v=Jo8yWhGpzBw

The Water (Engfa-Charlotte)
https://www.youtube.com/watch?v=Kp7DuZWZPnE

The Earth (Apple-Mim)
https://www.youtube.com/watch?v=4saGWsEzZg0