Places in the Never Never will be places designed for particular groups of immortal like the Stone Table, they won’t necessarily work for all, and like the Stone Table are likely to be designed to redistribute that Immortals power, involuntarily.
Greek Gods for example had no such place, they just couldn’t be killed, only reduced, however the same may not have applied to other pantheons, Balor for example was killed by Lugh, and this may have at been such a place for the Fomor.