In two Voyager episodes, trips to the Q Continuum are made. On both of these occasions one of the Qs had to "change the scenery," so that the humanoid brains of the away team could have some sort of understanding of what was going on. If the scenery was not changed, then the Continuum would be way beyond the comprehension of everyone, including Tuvok.
As it is with the appearance of the Q. Obviously, they are not humanoids---they appear in this form in order that humanoids can relate to them. A Q appearing in his true form would surely be beyond the ability of lower races to comprehend.
So, are any species from Star Trek lore capable of viewing the Q Continuum in its true form?