#4 Ousmane Dembele (tied)

Just a year after Manchester United made Paul Pogba the most expensive footballer on earth, Barcelona broke the bank to sign 20-year-old Ousmane Dembele from Borussia Dortmund in 2017. But, La Blaugrana just about equalled the transfer record instead of breaking it, paying a fee of €105 million for the Frenchman.
Looking at Dembele's career graph tells you how meteoric his rise has been. Currently, in his fourth year as a professional footballer, the Frenchman has swapped 3 clubs in the last three years before joining his fourth club -- FC Barcelona.
However, the youngster hasn't seen enough game time at the Nou Camp owing to his injuries, currently failing to justify his price tag. But the handful of games he has played in, Dembele has shown flashes of his huge potential.
His ability as a footballer can never be questioned, considering how he finished behind compatriot Kylian Mbappe in the race for the Golden Boy award.
Recently, there have been reports of Barcelona planning to offload him in the near future. However, the Catalans would do better in keeping him. Once he returns to being a regular, my word, Ousmane Dembele is going to a player to watch for sure.