I feel that there should be the Ultimate "ultimate" element type spells. For instance, Greater Pyro Blast would be the "ultimate" fire spell a mortal could cast as a spell scroll. Divines could have access to these Legendary spells as an actual card, or even spells that overpower those legendary spell scrolls.
Then where is the immunity to certain elements, such as the baby dragons from the Den of Devils campaign. They are immune to fire magic as they are offspring of the fire dragon.
But what I think would go far beyond is a "super" form. Take example of the Gumioh. There had to be the first one, correct? The first Gumioh could be a divine, and it's "super" Gumioh form would be a massive tile with far more tails and stronger auras.