Limbo realm

Limbo realms or Limbo dimensions were “zones of indeterminacy” that existed in-between more coherent universes and dimensions, dream-like and hazy. Some Limbo realms were beneficent and peaceful, while others were hellish or abstract nightmares; others yet were endless stretches of grey fog. Limbo dimensions often “grew out of peoples’ dreams, taking root in the indeterminate non-space and giving it form”. (PROSE: The Hermetic Garbage of Jenny Everywhere)

During a battle against some goblins, RagBoy and Hands McGee found themselves trapped in a void-like dimension and were rescued by Doctor Know. He described this realm as "the dimension many call Limbo," a "realm of lost imagination" where ideas can get lost. Doctor Know stated that this world did not exist as they would understand it, and to escape they had to go somewhere that did exist. (COMIC: Nighthawks)

After the collapse of the cosmos, various Limbo realms remained in existence, separate from the bulk of the Collapsed Cosmos, from Faerie, from the Redoubt, and for those areas of reality taken over by Chaos. Jenny Everywhere, Glendalf and the unconscious Octobriana took refuge in one through the tunnels under the Red Lion Inn, thus placing themselves beyond the reach of ARCHONET and that of the Wild Hunt. That Limbo realm resembled a forest covered in thick fog. (PROSE: The Hermetic Garbage of Jenny Everywhere)