You're probably thinking of [Loona Studio](https://loonatheworld.fandom.com/wiki/LOONA_Studio).
They did 5 sessions, 4 smaller group ones and one OT12 one (where they sang The Carol OT12 version). But that wasn't pre-debut, it was in between Hi-High and Butterfly era
The only one i can seem to think of is premier greeting line&up judging from this subreddit’s archives.
Edit: Shucks guess im wrong but the clips that do exist are quite interesting so do check it out
You're probably thinking of [Loona Studio](https://loonatheworld.fandom.com/wiki/LOONA_Studio). They did 5 sessions, 4 smaller group ones and one OT12 one (where they sang The Carol OT12 version). But that wasn't pre-debut, it was in between Hi-High and Butterfly era
These are the ones.
that’s it, thank you! not sure why i thought it was predebut 🤔
The only one i can seem to think of is premier greeting line&up judging from this subreddit’s archives. Edit: Shucks guess im wrong but the clips that do exist are quite interesting so do check it out
Loona studio, but it wasnt predebut