What occurs to me in regards to your inquiry is that God is beyond anything we can conceive of as nde experiencers report and nothing in our embodied state can adequately represent Her/Him/It. Any attempt to reify ( it him her) creates a demigod and not the absolute. God by definition has no beyond.
The German medieval mystical theologian Meister Eckhart provocatively wrote of the need to reach beyond God to the Godhead, which is not ultimately something substantially different from God but rather is God in Godself as the nondual "no-thing" that exists in eternity, is greater than all our conceptions, and in which we live and move and have our being:
“Why I pray God to rid me of God is because conditionless being is above God and above distinction. It was there I was myself, there I willed myself and knew myself to make this man. In this sense I am my own cause, both of my eternal nature and my temporal nature. In my birth all things were born, and I was the cause of my own self and all things.”
“I will put into plain words what St. Paul means by wishing to depart from God. Man’s last and highest leave-taking is leaving God for God. St. Paul left God for God: he left everything he could give or take of God, every concept of God. In leaving these, he left God for God since God remained to him in his essential self, not as a concept of himself, or as an acquired thing, but God in his essential actuality.”
There is an echo of Eckhart in the writings of the Sufi Muslim theologian Ibn Arabi, who contended that there are as many Gods as there are persons, insofar as every conception of God is in part the fashioning of an idol. Arabi also proposed contemplative detachment as a path toward recognizing God beyond the limitations of name and form.
[T]he language of theism gets God's melody right, but the sense that is hidden in his final depths rises above it. In technical terms, God is the object of kataphatic theology (what can be spoken), the via affirmativa; whereas Godhead is the object of apophatic theology (what cannot be spoken), the via negativa. The line is not hard and fast, but priests and prophets tend to focus on God, mystics on the Godhead. And the latter tell us that in those rare, supernatural moments when the Godhead is directly disclosed to man, what man then sees is that he cannot understand its character at all. It is not that depths of its nature remain opaque and ineffable; its simplicity precludes ladling things out this way. Its entire nature reposes in depth unfathomable. So the incomprehensibility of the Godhead becomes evident at the precise moment that its nature is most clearly apprehended - there is no way to state the point less paradoxically. In the light of mystical vision, the Godhead's hiddenness is not dispelled; it appears. Not that there are two Gods, of course. It is just that his/her single nature does not stop where our minds do.
Depends on what you mean. If God is the Ground of Being as described by philosophers (see the Catholic Scholastic Tradition following Aristotle and the Indian Vedic tradition - I think Patanjali might be good? @billw?), then yes in a very specific sense nothing is "beyond" God. A more modern take might be There is a God by converted atheist Anthony Flew (note he never accepted post-mortem survival).
If you mean a particular being who shows up in scriptures (or even NDEs) it's more questionable. Gordon White, who has a Chaos Magic blog Rune Soup, one said in a lecture describing what he saw as spirits influencing history that he was tempted to think, "The spirits are real, the gods are just in your head."
Beyond that Gnostic Christianity suggests the the "God" of Scripture is a pretender, one of the jailers of this world.
For classical theism, which is as close to a consensus as you can get in comparative religion (see David Bentley Hart, The Experience of God; Huston Smith, The Forgotten Truth; Reza Shah-Kazemi, Paths to Transcendence), the term "God" only rightly designates that which is Absolute: the infinite, simple, omnipresent, omnipotent first cause and ground of all existence. To suggest that something may be beyond God is as absurd as claiming the painting exists outside its frame.
In a mild pushback to Sciborg's post above , this tradition affirms that the infinite transpersonal God also manifests as the personal, loving, interactive God with whom one may have a relationship. The above books will be helpful in spelling that out, as well as this talk last year by Dr. Eleonore Stump on "The Personal God of Classical Theism."
But that's exactly what I'm saying, whatever God is there cannot be anything beyond god, because if there were anything beyond that God whatever is beyond would now be God. God is the greatest possible being, the boss of all bosses, the big cheese, etc.