7: Dele Alli - MK Dons to Tottenham

It seems crazy to think that Dele Alli only made his Premier League debut three years ago. The World Cup semi-finalist has become one of the best midfielders in the division and there is every chance he will move on from Tottenham to play for one of Europe's big clubs in the future.
Spurs signed Alli back in 2015 from MK Dons, spending £5 million on the then 19-year-old. The North London club would loan Alli back to MK for the remainder of the season, and he would help the Dons finish second in League One and gain promotion to the Championship.
Since then, Alli has been instrumental in Tottenham's success, scoring 46 goals in 146 appearances and making the PFA team of the year in two of his three seasons at the club.