A strange pocket dimension made of "Death Energy". Not much is known about it except that its purpose is to draw out the souls death from every Dimension and Timeline and turn them into the aforementioned energy. According to legends there exist some sort of link between this realm and Anur Vladias.
Dimension 7/Demon Realm
A dimension that is equal to the idea of Hell from human religions. It's home of many demonic species, including the children of "Death Energy", the Umbr' Magum.
Dimension 8/Light Realm
The dimension where Duplex Tribulatio takes place. This's main timeline dimension followed the main timeline of Earth-10 for the most part with a boy named Ben Tennyson discovering the Omnitrix, becoming a hero and leaving behind himself a legacy of prosperity and peace. What Dimension 10 differs from the main Earth is the future, where Xin Tennyson, one of Ben Tennyson's descendants tried to take over the Intergalactic court in an event that was remembered as Xin’s Usurpation. This misuse of the Omnitrix caused Azmuth to take all of the Omnitricies that existed and disappear from the known galaxy. The Plumbers restored peace and no major conflicts have erupted ever since, causing major technological stagnation.
This is the dimension where Alex Lowell and Avice Fry come from. Due to currently unknown reasons, 5% of the newborn humans tend to have genetic mutations and/or special abilities. It needs to be noted that this Earth is dying due to overuse and destruction of its resources.
Dimension 20/Data VR
A dimension made completely out of data material, making it a sort of a Virtual Reality. Its the home of many data-based species, including the Cedoroids.
The time and space of this universe are in complete chaos that causes various kind of phenomenons to happen like the appearance of space and time warps or the fusion of numerous planets into a single existence.
A pocket dimension created by the Eterien to hold the most dangerous beings of the Multiverse. Currently, it's being watched by Tray.
A hidden pocket dimension created by Tray that contains the "Element of creation" that's used to create universes, dimensions, and timelines. Its a place where the rules of time & space hold little to no meaning.