Omniverse

Beyond the Transformers multiverse is the Omniverse, which consists of every possible reality imaginable. Most of them have no Transformers whatsoever, while many others are inimical to both human and Transformer life.

Primus wishes to join the Omniversal Matrix when he has completed his cosmic mission, and The Fallen has been classified as an "Omniversal Tyrant".

Fiction

Ask Vector Prime

Vector Prime described the Omniverse as the realm outside of the Transformers multiverse. Occasionally, quantum-string vibrations can cause other realities in the Omniverse to temporarily merge with the universal streams in Vector Prime's domain.

The planet Sandra is from a universe outside the dominion of either Vector Prime or the Alternity. Presumably, this would mean that it is from somewhere else in the Omniverse. Ask Vector Prime

Notes

• In the real world, the concept of "the Omniverse" originated from analysis of comic-book continuities. As coined by Mark Gruenwald, it meant the collection of all multiverses; for example, Marvel Comics had one multiverse, DC Comics had another, and the Omniverse encompassed both. This extended to all fiction, and in today's usage it is sometimes meant to include the real world as well.
• Obviously, the Transformers multiverse would fall under the above umbrella. While there have been crossovers between Transformers and non-Hasbro properties, such as Star Wars and some Marvel superheroes, the term "Omniverse" had never been specifically used around or within them. 2015's Ask Vector Prime feature finally canonized the concept of the Omniverse, existing "outside" the established Transformers multiverse.
• In the story treatment that Simon Furman originally presented to IDW Publishing for their comic series, he described a Unicron-driven, simultaneous threat to Generation 1 and Cybertron universes, as well as others unnamed. He called this "an omniverse in chaos".