Dream of the Blue Veil is a weird spell in TCoE that allows you to transport to another world, but it's very mechanically strange and it comes with a side bar on travelling between worlds/settings.
Dream of the Blue Veil 7th-levelconjuration CastingTime:10 minutes Range:20 feet Components:V, S, M (a magic item or a willing creature from the destination world) Duration:6 hours You and up to eight willing creatures within range fall unconscious for the spells’ duration and experience visions of another world on the Material Plane, such as Oerth, Toril, Krynn, or Eberron. If the spell reaches its full duration, the visions conclude with each of you encountering and pulling back a mysterious blue curtain. The spell then ends with you mentally and physically transported to the world that was in the visions. To cast this spell, you must have a magic item that originated on the world you wish to reach, and you must be aware of the world’s existence, even if you don’t know the world’s name. Your destination in the other world is a safe location within 1 mile of where the magic item was created. Alternatively, you can cast the spell if one of the affected creatures was born on the other world, which causes your destination to be a safe location within 1 mile of where that creature was born. The spell ends early on a creature if that creature takes any damage, and the creature isn’t transported. If you take any damage, the spell ends for you and all other creatures, with none of you being transported, which meantions something that preceded the material plane called the First World. WotC is up to something major, a huge shift. It might even be a D&D multiverse shaking event, beyond just a Realms shaking event. I've copy pasted the Intel from Dndleaks reddit.
Traveling to Other Worlds The Material Plane holds an ininite number of worlds. Some—like Oerth, Toril, Krynn, and Eberron—are well documented, but there are countless others. You and your friends may even have created some homemade D&D worlds yourselves! It was not always so. Various scholars speak of a primordial state, a single reality they call the First World, which preceded the multiverse as we know it. Many of the peoples and monsters that inhabit the worlds in the Material Plane originated there. After the First World was shattered by a great cataclysm—giving birth to the worlds that came in its wake—the progeny of the irst elves, dwarves, beholders, and other iconic creatures took root on world after world, like seeds scattered by a cosmic wind. If the musings of these great sages are true, every world is a relection—and in some cases, a distortion—of the First World. Transit between these worlds is rare but not impossible and can be accomplished in various ways. One such method is called the Great Journey, an epic voyage fraught with peril and littered with obstacles to be overcome. This journey most often occurs aboard a vessel powered by magic. Another method is the Dream of Other Worlds; travelers fall into a deep slumber and dream themselves into a new realm. The spell dreamoftheblueveil employs this method of transit. The most direct method is the Leap to Another Realm; a spellcaster casts teleportationcircleor teleport, aiming to appear in a known teleportation circle or some other location in another world. Whatever method you use to reach a world, the DM determines whether you succeed and where exactly you appear if you do arrive in that realm.