#2 Winner of the men's Royal Rumble match
By the start of Royal Rumble 2018, most WWE fans were certain that either Shinsuke Nakamura (SmackDown LIVE) or Roman Reigns (RAW) would win the men's Royal Rumble match.
The reason is simple - WWE had been building up Brock Lesnar vs Roman Reigns for the Universal Championship, and AJ Styles vs Shinsuke Nakamura for the WWE Championship at WrestleMania 34.
Since Lesnar was certain to be a no-show at RAW's Elimination Chamber, the fans could narrow the winner to Shinsuke, even before the show even began (had Reigns won the Royal Rumble match, WWE would not have had any selling points for Elimination Chamber).
However, this year the scenario is different. The winner could be from either brand. Even though the odds are high on Seth Rollins, there is no reason why Drew McIntyre, Braun Strowman, or even a superstar from SmackDown should not win it. The 2019 Royal Rumble match is unpredictable.