Elemental Plane

A setting that represents or is made of a concept/thing. It may be sentient, in which case it may also have an avatar running around. Elemental Embodiments are likely to have come from this place.

Compare Elemental Nation, which may be an example. Compare and contrast Anthropomorphic Personification, for when it's a person rather than a place.

Literature

 * The Five Forbidden Regions in the Xanth series: the void, the region of water, the region of fire, the region of earth, and the region of air. Each region is filled with terrain and weather that represent it: the region of water, for example, contains a lot of lakes and it rains often.
 * Death's Domain and the Palace of Time in Discworld. Both symbolizing their concepts as much as the Anthropomorphic Personifications who inhabit them do.
 * Robert Silverberg's novel Son Of Man is made of this.

Live-Action TV

 * There's a universe of shrimp mentioned as a gag on Buffy the Vampire Slayer/Angel.

Tabletop Games

 * In Dungeons and Dragons, there are many of these. The "inner planes" include planes of Air, Earth, Fire, and Water, as well as the planes of "Positive Energy" and "Negative Energy".
 * In the Planescape setting, the "outer planes" include a plane representing each of the Character Alignments, and the "inner planes" also include "quasielemental" or "paraelemental" planes such as "the Plane of Dust", "the Plane of Lightning", etc.
 * Module WG7 Castle Greyhawk. The Queen of the Honeybee Hive on level 7 opened a gate to the Demi-Plane of Flowers, a gigantic plain covered with every imaginable type of flower and plant.
 * 4th Edition takes the elemental planes and mixes them into one plane, the Elemental Chaos.
 * All of the Titans seen in Scion, as of yet. Of those that haven't been, it's safe to assume that the vast majority also are.

Video Games

 * World of Warcraft hinted at those in the past, but really went nuts with the concept in Cataclysm:
 * Deepholm, the plane of Earth, made of mostly shiny rocks and crystals.
 * Firelands, the plane of Fire, with lots of magma, ash, lava and hot air.
 * Skywall, the plane of Air, consisting of mostly clouds and wind.
 * The Abyssal Maw, the plane of water, typical underwater flair everywhere.
 * The Legend of Zelda plays this in spades. Every console game has a Forest theme, Fire theme, Water theme, Death theme, and Light theme.
 * EverQuest has a bunch of these. Indeed, an entire expansion is called, "The Planes of Power", which contains something like 15 different planes. And there are more planes from other expansions.

Web Comics

 * In The Order of the Stick (which is an Affectionate Parody of Dungeons and Dragons), Varsuvius was magically transported to "The Plane of Ranch Dressing".
 * Irregular Webcomic: The Infinite Featureless Plane of Death. Note that this is apparently a parody/shout out to Discworld, even though the author denies (in jest) ever reading that series.
 * In Dominic Deegan we've seen the Plane of Destruction, the existence of the other elemental planes is referenced occasionally.

Western Animation

 * The Family Guy episode "Road to the Multiverse" featured quite a few of these.
 * One episode of Fairly Oddparents had several. A character attempting to get to "Fairy World" ended up in "Scary World", "Dairy World", and "Hairy World".
 * One of several D&D references in The Grim Adventures of Billy & Mandy involved Grim trying to take Billy and Mandy to the elemental plane of fire.