#1 Joao Mario

Arguably the most likely to join United this window, Joao Mario has been linked with the Red Devils recently - a potential swap deal including the suddenly out-of-favour Henrikh Mkhitaryan has been mooted - and there's a good reason for it.
The Portuguese playmaker has been in-and-out of the high-flying Inter Milan squad, Luciano Spaletti implementing his rotation technique, but when he's played he's looked sharp - his vision, passing, and dribbling making him a menace in the final third. Mario's positional awareness and discipline would also make him a perfect player for Mourinho... and with his arrival, the creative burden currently shouldered by Paul Pogba could easily be shared with the Portuguese.