The known links between the planes and the methods of getting there from the perspective of the reigning experts on Toril (Faerun each line shows a known permanent portal between the different planes of existence which allows for fast travel. Two of those portals, namely the ones for the City Of Brass and The Abyss travel through something known as the Elemental Chaos an extremely dangerous primal path that no mortal knows how to effectively navigate. Once in it, many more planes are connected, and the various fiendish races move through it frequently to wage war on each other but it seems magic is the only effective way to move through the maelstrom. To be trapped in the Elemental Chaos is to be lost forever. The other side of this is the Astral Sea, which links to Toril in far more places. While some of the destinations of the portals of the Astral Sea lead to heavenly realms such as Celestia, others lead to hell dimensions like the Nine Hells and the Demonweb Pits. It is a mix of the glorious and terrible. Unlike the Elemental Chaos however, the Astral Sea can be travelled and with technology and magic working in tandem, great ships known as Spelljammers have been able to sail into the sky and beyond the edge of that sky into the infinite nothing that is the Astral Sea. Obeying none of the laws of nature known to the mortals, to sail the Astral Sea requires either brilliant madness, or great intellect; though some say the latter would preclude such travels. Outside of both of these, is the Shadowfell and the Feywilds. Worlds like Toril these three worlds seem linked and almost a reflection of each other, leading to Toril often named the Prime Material plane. Please Note: Scholars outside Faerun, find this Toril centric cosmology reductive and simplistic. Most are aware that Toril has recently become linked to the worlds known by others as Lorwyn and Shadowmoor, a binary system of linked planes that reflect each other. Faerunians have decided these worlds must reflect their own plane, but few outside Toril see the connections. This cosmology also conveniently misses off other planes such as Zendikar, Kaladesh, Innistrad, Ravnica, and many more that have all found connections within the Astral Sea to many of the same locations. Innistrad is in fact deeply connected to Toril with Barovia and it's Castle Ravenloft, lead by Lord Strahd being a figure of many a Faerunian legend. Still it is missing from the incomplete cosmology. Most telling is Eberron, the second most populous and influential of the mortal planes is missing entirely from the Toril cosmology though so is Toril missing from the far more simplistic and reductive Eberron cosmological maps. While Toril and Eberron have no direct link, their influence on each other is becoming greater with every passing generation as they influence many of the planes they share connections with.