#1. Aleister Black

Aleister Black has been a Superstar who has been handled very well since his move to RAW. A clear Paul Heyman favorite, the Dutchman is being built as one of WWE's future top stars. He's been protected well and has featured in many good matches since his jump to the red brand.
He was previously in SmackDown since his wife Zelina Vega was there too, but his run on the blue brand turned out to be a bit of a disappointment as he was hardly ever utilized. There was a spot for him, but WWE didn't feel the need to include him.
Paul Heyman has direct control of creative on RAW and has ensured that Aleister Black continues to be built as a possible World Champion. We don't doubt that Black can reach that level and to do so, he needs to remain on Monday Nights.
We don't see a move happening for Black in the trade and as of now, it makes little to no sense for him to be shifted to SmackDown for the sake of it.