I would say safe bets would be:
Conor
Sage
Wonderboy
Nothing is for certain but who knows, by the time 2 years passes or something there could be a new fighter, not at the level of say Conor (not talking skills, just charisma) maybe somebody like Jones who is pretty skilled at MMA. People forget we're not that far away from seeing kids who have been training MMA since they were kids.
There's always the play that new fighters can make big names for themselves fighting old faded champions and top tier fighters. Look how fast Johnny Hendricks went down in flames, it's a rollercoaster in a logical sense some of the UFC's moves drives me nuts but on the other hand from a business sense, I get why they try to make the most out of fighters like Conor or Rousey with the hype because they have to capitalize and capitalize fast, there's no guarantee the stars of today will be stars even a year from now.