But seriously, they've got some decent potential land names from existing IP:
- "Isle of the Lost" is where villains live in The Descendants.
- "The Shadow Realm" is a literal name in some IP (DuckTales, Aladdin) and general concept
- "Forgotten Lands" is a land in the Dreamlight Valley video game
- "Forbidden Land" as a variation might work
I could see any of those as a land-with-in-land concept, sort of like Storybook Circus, if they wanted to say it's all "Fantasyland" too. I think it's better marketing for them to say it's a whole new land though. The geography would be daunting as well.
I don't think they're going to use a name that invokes hell ("Hades", "The Underworld"), death ("The Graveyard"), or specific religious references ("The Devil's Triangle" from POTC). Doesn't fit with the MK.