#4 Brock Lesnar
The Universal Champion's first run in the WWE primarily kept him on SmackDown for most of those two years. Taking on SmackDown mainstays like Kurt Angle, The Undertaker, Eddie Guerrero, and John Cena, Brock Lesnar's short but impressive stint was a major reason as to why the 2002-2004 era of the WWE was dominated by SmackDown Live, as far as which show delivered the better product.
Lesnar's personality really shined back then, and his highly competitive feud with the Olympic Gold Medalist delivered in almost every way possible. And while his comedic side may have taken a back seat, aside from Boom Box Lesnar, his in-ring prowess has never been better.
One of the most dominant champions that the WWE has ever seen, Lesnar is now a three-time Universal Champion. And though he's currently wreaking havoc on Monday nights, who would be able to stop the Beast Incarnate from getting into the building? After all, Survivor Series would only be six weeks away at that point, and he'll have to defend his spot at the PPV should he still be holding the title by then.
In the past two years, he's defeated two WWE Champions at the event, AJ Styles (2017) and Daniel Bryan (2018). If he's looking to hit the trifecta, he'll have to take on the WWE Champion again this year, whether it's the current champ Kofi Kingston, Randy Orton, or somebody else looking to make a name for themselves against the Genetic Freak.