of all

Adverb

of all

1. Used as an intensifier with superlative forms of adjectives.
   • Best of all was the bicycle I got. First of all, I'd like to thank my agent. He was the greatest playwright of all.
2. Used as an intensifier with nouns to denote being ultimate.
   • Of all the queer collections of humans outside of a crazy asylum, it seemed to me this sanitarium was the cup winner. […] When you're well enough off so's you don't have to fret about anything but your heft or your diseases you begin to get queer, I suppose.1913, Joseph C[rosby] Lincoln, chapter V, in Mr. Pratt’s Patients, New York, N.Y.; London: D[aniel] Appleton and Company, →OCLC
   • Wolves, sensing the comeback of all comebacks was on the cards, kept pressing and set up an exciting finish when Ronald Zubar's header was judged to have crossed the line, even though it appeared that Nigel de Jong had successfully cleared the effort.2011 January 15, Saj Chowdhury, “Man City 4-3 Wolves”, in BBC
3. Marks a thing or person as a particularly unexpected or unwanted example of its category.
   • While on holiday in Spain, we ran into Mark, of all people.