I'm guessing they were more than just creatures with the pseudonatural template?
I had made my own Zoas a long time ago, they had a reflexive version of alter reality which they could use on every part of an action in addition to other abilities. They appeared, at least the one Solarius encountered, as a person with a slightly emaciated human face and body and a head that was about 90 ft wide and 100 feet tall.
Their faces were of roughly human proportions with their brains and skulls just being gigantic. I also made the one Solarius fought green with elf like ears and a light black beard with red and blue eyes. But the others she saw were different colored and had slightly different features, not all of them appeared humanoid but all appeared atrophied with massive heads.
They had pitifully weak physical stats but insanely high mental stats, but the thing that made them dangerous was their alter reality, called Alter Creation, had almost no limitations so they could just spam it and it would just rewrite reality around them. It could do any effect they so chose only limited to their or the DMs imagination.
They could do this as part of every type of action so as part of a standard, a move, a free, a swift and an immediate action. They could even use it as part of their 5 ft step. Basically they could use it offensively to create any effect they so desired and defensively to alter the situation in any way they please. I did this to mimic the idea that it was tied directly to their thoughts, not something they "do" so to speak but something they are.
In terms of power they were solid high demiurge level threats, capable of, if not checked, destabilizing the very universe of a Time Lord.
Their main weakness was someone sneaking up on them, they had little defenses, they had a high deflection ac due to their high Charisma but they only got spiritual growth levels of div abilities, which, at those levels is a massive disadvantage. They had low health, for their level, with very weak physical stats, roughly on par with a human.
That was another one of their weaknesses, they could change everything around them besides themselves, basically they were trapped in a perpetual schizophrenic loop of trying to prove intellectually that they exist, this forced them to always be in their true form.
They could make projections and "appear" as something else, but they were always just giant brain people floating usually in the far place or highly madness aligned areas of the pleroma in a constant existential argument desperately trying to prove to reality itself or more succinctly to themselves that they're valid and they exist.