#3 Marcus Rashford
One of the premier young talents in England and all of world football, Marcus Rashford is another key player that United need to keep a hold of. After initially breaking onto the scene in early 2016, he has been a mainstay in the United first team squad ever since.
During this time, he has made 162 appearances for the Red Devils, scoring 45 goals all across the frontline. Given his excellent pace, dribbling, and shooting ability, he has excelled when deployed as both a winger and a striker.
His success at the domestic level has also translated on the international stage, where he has made 31 appearances for England. Still just 21 years of age, Rashford has the potential to be one of the best players in world football.
Transfer rumours have linked him to some of the biggest sides in Europe, which would be a huge blow for United. Especially given the inconsistency of Romelu Lukaku up front, Rashford is a young gem they need to hold onto.