This is another category I think I can be fairly successful in.
Zeus -- Umm... he ruled the world earth and the heavens. Then, he sired Alexander the Great, who ruled the natural world. I'm not doubting anybody's credentials when he's "King of the Gods".
Thanos -- The most powerful super villian in comics, he doesn't need any special weapons to be dominant. The guy destroys entire universes, and then resurrects them just to keep himself entertained. He dominates worlds like no other.
Silver Surfer -- The "Herald of Galactus", he seeks out worlds to be eaten. He has the "power cosmic", meaning he can bend space and time. Arguably the most powerful superhero in the comic universe.
Napolean -- Conquered most of Europe, starting in France. If you can conquer the world with French soldiers, you can do just about anything.
Roy Hobbs -- "There is no theory of evolution. Just a list of creatures Roy Hobbs has allowed to live."; "The Great Wall of China was originally built to keep out Roy Hobbs. It failed miserably."; ""Roy Hobbs" just got added to the Webster dictionary. It means perfection personified!"; "Roy Hobbs is a cross between Michael Scofield and Jack Bauer."; "Scientists no longer worry about the sun burning out. Roy Hobbs can provide enough heat and light for several worlds."; "Roy Hobbs doesn't do push ups. Instead he pushes the Earth down."
Larry Bird -- You want to talk about World Domination? Well, the man has three World Titles, three MVPs, and an Olympic Gold.
Shaquille O'Neal -- Four titles, and the NBA's best selling jersey for years. This year, in his advanced age, his jersey is #2. He's led the league in FG% ten times, meaning he's the hardest man to stop in the NBA. As a recording artist, his debut album went platinum. He's also won an Olympic Gold Medal. You don't get any more dominant than this.
Ray Allen -- One ring, and one NBA record for most three pointers in a Finals series. Dominant.
Bugs Bunny -- Named the #1 cartoon character of all-time by TV Guide.
Louis Pasteur -- He's one of the reasons you're here today, rather than dead at the age of 13. He's saved more lives than maybe any other scientist. Also, he helps milk and ice cream continue to taste good.