#3 Antoine Griezmann (Atletico Madrid to Manchester United)

What a signing Antoine Griezmann has been for Atletico! Joining from Real Sociedad in the summer of 2014, Griezmann developed himself from a promising talent to a player on the level of Messi and Ronaldo, at least in his own right. He underwent a changed in position, moving to a more central position as opposed to out wide.
He added more assists and many more goals to his game and became Atletico's talisman. When he arrived after the World Cup in Brazil to replace Diego Costa, one didn't know what to expect of Griezmann. He leaves with nothing left to prove.
The 2018 World Cup winner confirmed he'd be leaving Atletico in the summer, and though he did not mention his next destination, Barcelona were thought to be long-time admirers, and clear favourites to pair him up with Messi.
However, Manchester United have reportedly barged in and are determined to steal Griezmann away from Barcelona's hands. If they can manage to do so, it'll be one of the biggest signings in recent Manchester United history, and one that will certainly improve their roster a fair bit. Moreover, it might be a case of necessity more than luxury, as the Red Devils are considering selling their star striker.