This would me a plane that has affects upon the Material Plane?
Perhaps a Plane of Dreams?
Perhaps a Plane of the Gods.
Perhaps a Mirror Plane, where everyone's Evil twins exist.
Hm... this Plane, having it's affects upon the Material Plane, would is a way be superior to the Material Plane. If there is a one way effect, this Plane would be "real" and the Material Plane would mimic it, in a sense.
A Dream Plane could inspire people to act in a way to make what's shaped within the Dream realm into the real world.
A Deity Plane would be able to affect the Material in that whichever god is active or currently in control affects the alignment and areas that are included within that god's portfolio. However the gods fight/negotiate/manipulate each other for supremacy. If a Neutral Evil god of pestilence has gained the upper hand in the godly realm, the Material World will look differently than if the Chaotic Good god of fertility is currently running things.
With the Mirror Plane, each plane would effect each other in a way. This concept always seems to break down under reasonable scrutiny, but as long as you don't think about it too much, there can be a world where everyone's got an opposite twin, and yet the events of history unfold similar enough.
How about a Feral Plane, similar to The
Beastlands, where the world is as is, only without sentient life? All continents and climates are the same but no cities, no roads, and all the critters are bigger. When civilization rises to large or people start abusing nature to harshly, that plane presses into the Material Plane and some degree of chaos brings things down.