Therea are many types of planes out side the Material Plane of the world you may know.
Demiplane
A pocket dimension of finite size created from the raw protomatter of the Ethereal Plane. Certain spells can create demiplanes, usually as temporary locations, and some magical items access demiplanes as part of their enchantment. Many demiplanes can be accessed directly through a portion of the Ethereal Plane known as the Deep Ethereal but others are locked except through specific portals or gates.
Echo Plane
An alternate dimension that lies tantalizingly close to the Material Plane harbors some mirrored facets of it, although not wholly embodying every aspect. These realms, often described as resonant “echoes” of the Material Plane, are believed by numerous planar scholars to be under the influence of a potent, unseen external force. The Plane of Shadow stands as a testament to this connection, intricately linked with the foreboding Negative Energy Plane, forming a stark counterpoint to the Plane of Faerie, which draws its essence from the nurturing Positive Energy Plane.
Adding depth to this complex network of dimensions is the enigmatic Plane of Dreams. Here, the well-defined contours of the Material Plane yield to the swirling, imaginative vistas sculpted by the dreaming minds of sentient beings, creating a realm where reality is persistently reshaped and reimagined. Meanwhile, the Ethereal Plane unfolds itself into two distinct regions: the Border and the Deep. The Border Ethereal, in particular, epitomizes the concept of an echo plane, offering a unique perspective into the multilayered, intertwining realities that paint the grand cosmic world.
Energy Plane
A realm either entirely or partially forged from unbridled energy characterizes the distinct facets of the Energy Planes. Currently, two prominent Energy Planes are identified: the Positive and Negative Energy Planes, which encapsulate the fundamental sources of radiant and necrotic energies, respectively. While these planes present a harsh and hostile environment to life forms, certain accessible pockets of refuge can be found within. Intersecting with both the Inner and Material Planes, these vibrant Energy Planes foster zones of amalgamated elements, providing destinations that adventurers can potentially explore and experience.
Inner Plane
A plane that embodies the fountainhead of one of the foundational elements of existence—air, earth, fire, or water, stands as a cornerstone in the vast cosmos. These realms are colloquially termed the Inner Planes, revered as the heartbeat of the multiverse itself, and at a metaphysical juncture, perceived to constitute the very nucleus of the acknowledged reality. Each elemental essence thrives within its own boundless domain, yet the Inner Planes engage in a dynamic interplay, fostering transitional zones where compatible elements coalesce. This phenomenon gives birth to hybrid planes such as the Plane of Ash at the convergence of air and fire, and the Plane of Ice, where air embraces water, crafting an intricate tapestry of elemental synergy that unfolds across the cosmos.
Great Wheel
The primary classification of the planes, as acknowledged by planar scholars, revolves around geometrically cohesive concepts. Wheels, spheres, and circles recurrently emerge as common themes amidst the planes of existence, leading scholars to associate the sprawling multiverse with the notion of the Great Wheel. Occupying the central hub of this Great Wheel is the Material Plane, encircled by the foundational Inner Planes. Further encompassing these layers in a celestial dance are the enigmatic Outer Planes. It is worth noting that this perspective stands as merely one theoretical framework attempting to decipher the complexities of the multiverse, and alternative theories, potentially holding equal merit, are also explored by thinkers in this field.
Layer
A segment of a plane of existence characterized by distinct physical or metaphysical attributes. A considerable number of the identified planes encompass multiple strata, which predominantly operate as independent entities yet are seamlessly integrated into the wider plane through readily accessible portals and gates. These intricate connections allow for fluid transition and exploration within the multidimensional realms, fostering a complex yet coherent cosmic structure.
Material Plane
The dimension residing at the nexus of all other existing planes, the plane of existence, frequently referred to as the Prime Material Plane, embodies fragments of all other planes, harmoniously blended in diverse proportions and quantities. These planes are boundless in their expanse and complexity, exhibiting a vast array of characteristics as observed in the rest of the multiverse. Despite this, they constitute the central framework of what the majority of beings perceive as “reality”, serving as the foundational bedrock upon which the familiar aspects of existence are anchored.
Multiverse
A broad term employed to encapsulate all the recognized planes of existence. The theories outlining the interconnectedness of the multiverse are manifold; among them, the Great Wheel cosmology is prevalently acknowledged. However, a spectrum of alternative theories also endeavors to elucidate the complex web that binds the various realms in the multiverse.
Outer Plane
A dimension characterized by prevailing philosophical energies, the Outer Planes form a critical part of the Great Wheel as identified by most planar sages. These sixteen delineated realms are largely understood to align at the crossroads of moral and ethical spectrums, representing good/evil and law/chaos dichotomies in various combinations, inclusive of neutral zones where these forces may be absent.
For instance, Mechanus embodies the epitome of order and law, existing in a state untouched by the influences of good or evil. Contrarily, the Abyss signifies the manifestation of sheer evil intermingled with chaotic tendencies. Remarkably, several Outer Planes, particularly those at extreme positions on these spectrums, extend support to entities that resonate with their underlying philosophies. However, these planes maintain a semblance of neutrality, seldom exhibiting outright hostility towards travelers who do not align with their foundational principles.
Transitive Plane
A plane fundamentally designed to facilitate transition or connection, the Transitive Planes are chiefly recognized as the Astral and Ethereal Planes. The Astral Plane, a peculiar domain where the passage of time diverges from the norm, functions as the universal linkage or “fabric” intertwining all other planes of existence, establishing a network of cosmic connections. Meanwhile, the Ethereal Plane also holds its status as a Transitive Plane, albeit its connectivity is limited to establishing direct links with the Inner and Material Planes, serving as a mystical bridge that binds these primary realms of reality.
May want to read about Understanding Demiplanes: An Exploration into the Unknown
