#1 Cristiano Ronaldo

It comes with little surprise that Cristiano Ronaldo takes up the number one place on this list. Although his £80 million price tag may seem like small change compared to transfers of the ilk of Neymar to PSG, at the time this was a huge deal. As a matter of fact, it was a world record fee, shattering Zinedine Zidane's record.
Ronaldo had already won the Champions League and the Ballon d'Or upon signing for Madrid, and with it brought a lot of expectation from both the club and the fans.
The Portuguese arrived when Barcelona were in the midst of their dominance over the football world and many saw Ronaldo as the one to spearhead a challenge to Madrid's Catalan rivals.
Many would be fazed by this daunting task being put on their shoulders, but Ronaldo wasn't. During his time at Madrid, Ronaldo scored an unrivalled 450 goals in 438 games, won 4 Ballon d'Or's, 4 Champions League titles and more.
Despite being there for 9 years, Ronaldo now owns virtually every significant record at the club and is arguably the club's best ever player. He may be at Juventus now, but his absence is painfully clear in Madrid and it seems certain that he is an irreplaceable player that Real Madrid were lucky to have had among their ranks.