A "prime" Danny Williams, if such a thing exists, is just about the only fighter on there who could beat him. I reckon Audley has the boxing ability and natural talent to cause him problems, but wouldn't acquit himself in the moment of truth. Haye might, he had the speed to do it. Hide, possibly, but I think Bruno knocks out Hide before Hide gets to Bruno.
diSaw Him Spar with a few mentioned, Akiwandi lasted a Round some others did a bit better. But not much.
Bruno did exceptionally well to win a world title. He would never have been undisputed champion, even in the poor division that exists today.
I believe Bruno proved it took something special to beat him. 'Something special' doesn't appear on that list of heavyweights.