From a purely personal curiosity stand-point (not a good for the country/world way) I'd be interested in an Ivanka Trump run. But I don't think it is likely; DT Jr. might but that would end in disaster - he's far too meek and lacking in self-esteem from a lifetime of living in his father's shadow.
Oprah is totally a narcissist too - you have to be to want a TV show, magazine, and cable channel named after you - , but not an insecure, paranoid, idiot one. I expect she'd be like a less competent Trudeau - she'd spend her time touring the world making happy speeches (though without the skilled diplomacy of Justin) while leaving most actual governing to more competent people.
We'll never get a totally normal person because a certain degree of arrogance is required to think you deserve/want to run the most powerful country in the world and put up with journalist analyzing every moment of your life to do so.