#4 Iago Aspas (Spain, Celta de Vigo)
Goals scored this season - 9
The Spanish Center-Forward knows his way to the goal very well. He scored 26 goals from 49 games in all competitions in the 2016/17 season and followed it up with 23 goals from 37 games in all competitions last season. So far this season, he has already scored 9 goals from 12 games, including 8 from 11 games in La Liga.
Aspas has an exquisite first touch and a brilliant left foot, but he is equally adept with his right. Blessed with speed and an eagle for the goal, the Spanish striker is quite different from Lukaku but would thrive in Mourinho's counter-attacking system. Another advantage of Aspas is that he is comfortable playing on the right wing too, which could suit United nicely. Age could be a concern since he is 31 already, but United do require experience in attack.
While Aspas's consistency might be a problem - his goal scoring has been sporadic so far, he could be an able deputy for Lukaku, but he will cost at least £22.5m. Whether United are willing to splash the cash for a 31-year-old remains to be seen, but Aspas definitely has the ingredients that would entice United in January.