#1 Cristiano Ronaldo
This has been the greatest export in Manchester United's history. When Ronaldo joined from Sporting Lisbon, he had the same fire and potential of the Brazilian great whom he shared a name with.
Ronaldo evolved from a great player at United to a living legend when he moved to Real Madrid on a world record fee in 2009. At the time of his departure from United, he had won nine trophies - including three Premier League titles.
At Madrid, he scored over 30 goals in each of his nine seasons at the club. He left the club having scored a whopping 450 goals to emerge as their all-time top scorer. It is hard to imagine anyone ever coming close to that record.
Ronaldo was instrumental in most of his 15 trophies with Madrid. He was the top scorer for the side as Madrid won four out of five UEFA Champions League titles from 2013 to 2018.
What more could Ronaldo have achieved at United had he stayed? We will never know.