Cahyali: A smaller world where adventurers also hail from, which features much larger landmasses than Jearn.
Infero: The land of the dead, the fallen, once-beautiful plane of Cielo. It is the passing place that souls go to before reaching their afterlife.
Kurago: A plane of existence attached to most other planes.
Alpha Site: The Centralia Guild of Wizzards extra dimensional portal farm
The Planar Sea: The extradimensional space that planes of existence, well, exist in. Theoretically inhabitable to life (that we know of), and there is no current way to travel to the Planar Sea.