Far Realm

The Far Realm is H.P. Lovecraft's magnum opus one of the more obscure planes of Dungeons & Dragons, and basically amounts to the obligatory "Cthulhu Mythos Dimension" for Lovecraftian horrors. It is formally considered an invention of 3rd edition, although Lovecraftian tropes were in D&D lore from the very beginning - like the first Deities & Demigods, for which Gygax's ass got royally sued. It was Bruce Cordell's 2e adventure "The Gates of Firestorm Peak" which named the plane "Far Realm", and since nobody sued him that's what stuck. 3rd edition merely expanded on the details most highly, which, combined with the fact it isn't formally placed on the Great Wheel, is why most consider it a 3e invention.

The Far Realm is generally described as, or believed to be, the origin-point for all aberrations (although a moment's thought would indicate that aberrations could only be touched by the Far Realm at some point in their evolutionary history, as native entities actually plane-shifted out of the far realm drive PCs insane just from being looked at). The exception is in Eberron where they are instead the creation of the daelkyr.

Ironically, the Far Realm was about the only major plane to survive completely unchanged when 4th edition switched from the Great Wheel to the World Axis. It is still the mysterious alien realm from which aberrations are believed to spring and about which little is known. It's actually quite important to the Nentir Vale setting; shardminds were born when a cosmological construct keeping the Far Realm at bay was acidentally broken by some of the gods, whilst the energies pouring through that heavenly wound are suggested as one possible source for psionics.

Creatures from the Far Realm

Please note that many of these creatures have multiple origin stories so whether they are from the far realm or somewhere else depends on what edition and setting you are looking at.

• Gibbering Mouther (Depending on the edition they may be from the Realm or formed from corpses left near Far Realm portals, or have a completely different origin if this is from before the far Realm was added)
• Beholder (Mainly in 4th edition)
• Neh-thalggu
• Grell
• Flumph. Not everything from the Far Realm has to be evil
• Foulspawn
• Kaorti. Accidentally created from a group of wizards that tried to set up a base in the Far Realm and were warped when Zurgurth tried to examine them.
• Uvuudaum. From the Epic Level Handbook. A bizarre and extremely powerful creature that has 8 human like arms but no legs and a giant spike where it's face should be. Also apparently the overlords of the Far Realm.
• Zurgurth the Feasting Vast. An Elder Evil resembling an ocean of flesh.
• Father Llymic the Alien Thought Given Flesh. An Elder Evil resembling a three-eyed scythe-armed ice monster who spreads a disease that turns the infected into similar monsters.
• THOON: Something that some Illithids worship but will not or cannot explain what it is.