#2. Is ready: John Cena

While we're aware that this match is very unlikely to happen during Braun Strowman's Universal Championship reign, it's one that we wish we could see. Strowman and Cena have faced off before on RAW before Elimination Chamber 2018, but it ended with a dusty finish, presumably due to WWE wanting to save the match for another time.
John Cena's last feud was with 'The Fiend' Bray Wyatt, who he faced inside the Firefly Fun House 'match'. It wasn't so much a match as it was an extended segment, but it saw Cena put over Wyatt and vanish.
Where is The Big Show today? He tells us HERE
Since 2016, Cena hasn't returned much post-WrestleMania and with his increasingly busy Hollywood career (which could be on halt for now) and the current circumstances, the chances of him returning to WWE later on this year are a bit slim.
If he does return, then the best option would be for WWE to book a face vs face feud between the two. Cena is one of the greatest of all time, so he'll always be ready.