Great fighters Tyson beat (off the top of my head):

Ruddock (as said - twice; Razor was a champion-quality heavyweight--who got lazy & turned to drink if I remember right; Tyson fought him at his very best); Frank Bruno (twice - & easily); Tony Tucker (great fight); Bonecrusher Smith (who was generally dominant--but was known for training lapses & losing fights he shouldn't have; he was ready for Tyson--& got destroyed); though I wouldn't call Golota & Spinks great fighters--they both were dominant & both had very good victories under their belts (Spinks mostly as a light heavyweight though)--& both quit outa fear after feeling Tyson's power.

But the real telltale of how badly Tyson dropped as a fighter from the 80s to post-prison 90s was Larry Holmes. Though Holmes was past his prime in '88, to say he wasn't a great fighter would be laughable. Tyson absolutely destroyed him in just a few rounds (& Larry fought like a champ--very bravely coming back from some vicious shots to the chin that put him down hard). Larry fought for like 5 more years though--& I was on my mission ('92 or '93) that he & Evander (who I really liked) went the distance — w/ Evander winning in a decision. That was when Evander was Champ (& Mike in prison, of course). So, iows, the oldish (but still good) fighter that Tyson destroyed in the late 80s went the distance w Evander 4-5 years later — when he should probably been headed into retirement.

Sorry for taking a shot at your basic knowledge, but Tyson dominated in the heavyweight ranks like few others have. And it wasn't simply for weak competition. Unfortunately Mike was a pretty self-destructive individual (but a pretty interesting guy, too).