Don't forget Armstrong's stoppage of a Zivic! That's not a joke...but i'd rate Saddler slightly above him, personally.
I was right with my opening sentence on the pargraph above. The Cobra - Armstrong or Arguello. McGrain - Saddler, or do you mean having him above Armstrong and not necesarily #1? Sweet Pea - Lopez or Hamed.
Saddler. His knockout percentage was over 60% and thats not bad going considering he had 162 fights. Zuelta was to Saddler what Soto and McCullough were to Hamed. Pep was rather durable, but Zuelta was as tough as a concrete wall. He wasn't stopped in 124 fights and Saddler couldn't stop him over two fights. However, knockout percentages on paper can be misleading to a certain degree. High percentages can also mean that a fighter is great with accumulation rather than 'outright' raw power being the reason for so many stoppages. Duran at lightweight is a classic example. A superb puncher. But he never made opponents fall like Hamed or Hearns. Duran was the type who would pound opponents and take them out down the stretch brutally. If you look at his defenses at lightweight, it supports my claim. Outwith the tomato cans he was was fed in non-title bouts, his stoppages were mostly down the stretch. A serious puncher takes opponents out early when physically and mentally they are tuned. Tyson, Hearns, Louis, Hamed, Jackson, Shavers, etc. All level 1 punchers. Duran level 2.
Most of Duran's stoppages did come as a result of one or two punches turning things very quickly, without being one-punch knockouts per se.In that area of being more than a wear 'em down puncher, but not quite consistent one-shot either. he's a bit like Ruben Olivares in that respect, or zarate.
Lightheavy-Fitzsimmons, Moore Lightweight-Duran,Arguello Featherweight-Saddler, Hamed Welterweight-Trinidad,Robinson
from heaviest to lightest gotta say Louis/Foreman, Foster, Robinson, Arguello, Lil Red Lopez/Hamed no snap, crackle, and pop here. just pop. my apologies to the many ko kings i didn't mention, but these come to mind
A few notables, pure power wise Shavers Foster/Spinks Hearns/Jackson SRR/Cuevas Rosario Arguello Hamed/Saddler/Lopez Gomez/Garza Zarate/Olivares Wilde