#2 Roman Reigns
He might be away from the company for health or other reasons but the fact still remains that Roman Reigns was slated to take the Universal Championship from Goldberg at WrestleMania 36. We know that he was unable to compete and Braun Strowman took advantage of the opportunity.
Strowman is currently feuding with the former Champ, the Fiend Bray Wyatt, but he's only facing the Firefly Fun House version of the former Eater Of Worlds at MITB. That likely means that some chicanery might lead to the Monster Among Men retaining his title. It would then lead to an eventual match against Wyatt's alter ego, the Fiend.
Whatever happens at MITB, it appears that Strowman might be having a short title reign. The original plan was for someone else to win the title at WresteMania 36 and that was Reigns. Prevailing circumstances prevented The Big Dog from showing up. If things have slightly changed by August regarding public gatherings and health restrictions, then we can expect to see Reigns return beforehand.
Regardless of when restrictions are lifted, it stands to reason that Reigns will slate back into the title picture. Up until Mania, The Big Dog had been away from the title picture ever since returning from his health hiatus. He'll get back into the picture in the second half of 2020.