#1. Paul Pogba

Paul Pogba was the most expensive player at that time when Manchester United signed him from Juventus in 2016 at the reported fee of €105 million. There was a lot buzz around Old Trafford when he came in as many believed that he would be that pillar in the United midfield.
Despite not performing to his best in his first season under Jose Mourinho, the Portuguese did back his talisman and confirmed that he would eventually come good. Paul started the second season on a high note scoring two goals in the first two games but gradually inconsistency crept in, and the manager's patience ran out.
Even before the current season started, shots were fired from either end, with the manager saying that the World Cup format favoured the Frenchman more. Pogba also added fire to the fuel with his comments about a move away from Old Trafford. Paul even questioned United's style of play after the draw against Wolves this season.
He is one of the best midfielders in the world right now and with Barcelona and Juventus lurking in the shadows, if he leaves, it would be a significant loss for United going forward.