Supra means "above/higher than"
Celestial means "heaven"
So, Supra celestial means "Higher than heaven."
Are there any beings higher than heaven? This depends on one's definition of heaven. If you take it on its original meaning: "sky" then yes. Humans have been above the sky, many times. If one takes it in a more figurative way to mean "the abode of God" then I would say no, no being is higher than God. There are probably other ways to tweak one's definitions to get whichever answer one wishes.
So the answer is: Yes, No and all things in between.