#3 Memphis Depay
One of the better signings of United under Louis van Gaal, Memphis (didn't want 'Depay' to be associated with him due to his history with his father) had been assured of a very promising career at United.
His physique was well appreciated by the everyone around him and it seemed like LVG had played a master stroke by signing him from PSV in 2015 for £25 million. He had all the skills in his armory, blinding pace and world class technique.
His poor performances were what caused his doom at United, he fell out of favour with LVG very soon and even though came on as a substitute in many matches and provided those super sub performances, he never really caught the manager's attention on the pitch.
He was offloaded to Lyon in January 2017 by Jose with a buy back clause, but that, it seems was just wishful thinking on United's behalf as he has yet to prove himself over there as well.