I see few info regarding this when I try to search online, so I made this while I’m trying to complete exploration in some maps. Sharing this here in case anyone needs it.
It’s still in progress, will add more maps with hidden/isolated areas. Feel free to comment if I missed something (if something is not in the list, I might already completed it prior to creating this document, don’t hesitate to remind me ).
What’s missing so far:
Royal Mausoleum 1f
2nd Demon Prison