de omni re scibili ("of all things that can be known") was the motto of pompous young lad and famous Italian philosopher Pico della Mirandola who thought this was a fitting description of his encyclopedic knowledge
et quibusdam aliis ("and all kind of other things") was ironically appended by pompous old fart and famous French philosopher François Marie Arouet, dit Voltaire, who was somewhat under the impression he was any less full of himself.
In all fairness, it should be said that Pico della Mirandola probably meant it in a sense of goal, a laudable humanist quest to take interest in every aspect of knowledge, be it art or science.
As for the brilliantly witty and notoriously merciless Voltaire, he probably just could not resist tossing an easy one to a man he had, after all, taken much inspiration from.
This expression can be used to berate pompous people who seem to take some pride in the paper-thin illusion of their universal and versatile knowledge (the kind who write nodes on obscure Latin quotations and other unrelated topics). See "La culture, c'est comme la confiture: moins on en a, plus on l'étale..." | 
