Sorry to sully the forum with MMA, but I do believe that Jeremy "Your Mom's Next Boyfriend" Deleon deserves a mention.
I have The Executioner as my #6 on my top ten list. The Alien made it onto my top 50 also. Both great nicknames!
I always thought some bare knuckle fighters had strange nicknames, such as Peter Crawley “young rump steak.”
Probably mentioned but Don "The Lonestar Cobra" Curry is pretty badass. Most unique is Carl "The Truth" Williams. I also like Azumah "The Professor" Nelson. Worst is Johnny "The Entertainer" Nelson...
Derek "War" Chisora I am sure that some other boxers have this nickname, but I am not aware of it. Short, simple, and says it all.
Macho... Iron Dick Tiger is actually a nickname in itself as his real name was Richard Ihetu, and he fought Super Power Bomb and Monster Lion early in his career lol those Nigerians back then!!!