Clans of Tear

The inter-dimensional travelers that is a clan having multiple sources of operation traveling to try to find and map all the dimensions nearby the Earth realm

magical portals, hidden passages (like closets, mirrors, rabbit holes), powerful spells, or special artifacts, but it can also be achieved through altered states like dreams/lucid dreaming, exploring natural 'thin spots' in reality, or even manipulating the very fabric of space through 'tessering'.

Loading zones. Think of in a videogame where you enter an area that isn't loaded yet, but as the new area loads, the place you came from disappears. It could be hidden with fog, smoke, darkness, or something else, but there is the idea that the world just forms around you.

Blink. You are just suddenly there. Like one frame of animation you are at one place, then the next frame you are somewhere completely different.

Dreams. You don't retreat into your mind when you dream, but into another world. Could your dream self find their way to your "real body" and interact with it?

They get a swing set (maybe it's a magical pendulum device or something if you want to go fancy with it) and they rock themselves higher and higher. Once they get enough momentum to swing all the way over the top of the frame, they do a dimension flip, where the ascending part of the arc they're in dimension 1, at the pinnacle they swap over and the descending part of the arc then takes place on a linked swing in dimension 2.

The poor people of my universe travel through dimensions by going through the metaphorical garbage dump dimension

i.e. the universe's version of hell. Since the garbage dump is the only link that connects all worlds to each other, it is the only method known to anyone capable of planar hopping, even the gods.

Not a pleasant experience. Can also easily drive anyone insane, since the 'dump' has no concrete concept of space, time, or tangibility in general.