Very few concepts in general can truly be outside of the Omniverse; as the name itself implies the complete totality of all verses, as well as countless realms, dimensions, spaces, voids, etc. However for an omnipotent being like Creator this is just another concept below his/her level.
Being omnipotent^1 allows Creator to be beyond the very concept of existence. This allows the Godverse to be outside the limits (what few there are) of the Omniverse. Nonetheless the Godverse can still be classified as "existing", but the inner working of such a magnificent space is beyond any known level of comprehension. If anything within the heart of the Godverse is to exist, it would surpass every level of existence known and experienced by most within the Omniverse.
The Godverses and the Beyond Realm are the only two existences residing outside of the Omniverse. All three are surrounded by The Outside, a space/void encompassing the absence of existence. Anything surpassing (or perhaps very far out within) The Outside is only known as Beyond. All of this however is of course still kept within the much larger concept, The Box.