The phrase "knowledge of everything" is correct and usable in written English.
You can use it when you are referring to someone's understanding or comprehension of a wide range of topics. For example: "Although she claims to have knowledge of everything, her lack of understanding about basic physics showed she had a lot to learn."
He wanted knowledge of everything.
He was like a fountain of knowledge of everything that was cool, the coolest grandpa ever".
"I think he's very capable, very experienced, with a complete knowledge of everything around football and its organisation," he said.
He is an information hound, craving knowledge of everything from public opinion of himself to the game on the field to, apparently, wide-ranging topics off the field.
His knowledge of everything motorbike made me tentatively confident that, with a fair wind, I might even make it as far as Dover.
But it is perfectly possible that the world might exist and we could not prove it, let alone be able to obtain absolute knowledge of everything in it.
I'm not a total dork-ass knowledge bank of EVERYTHING Sad-Ass Music related (believe it or not), but I do have my head on pretty goddamned straight; or, shit, crooked depending.
The soul is improved by acquiring correct opinions and eventually knowledge on everything humans are capable of knowing.
Ahmed, who seemed to possess an encyclopaedic knowledge of, well, everything, and spoke faultless English, helped her choose.
Part of the problem is that Terkel himself has an encyclopaedic knowledge of almost everything and sometimes gets sidetracked by obscure, arcane tangents.
She also thought that the pet space could use more disruption, and as Chris and Kim built out the first version of Spotwag, "She was a great source of knowledge for everything from product features to PR".
