5) Islam Slimani (Sporting Lisbon to Leicester – £28m)
The Foxes snapped up the Algerian international after he scored 31 goals for Sporting during the 2015/16 season, but his goals begun to dry up after his move to England.
Slimani had a relatively decent first season at the King Power, although he wasn’t a regular starter, but his game time began to diminish in his second year and he had three loan spells before leaving for Lyon on a permanent basis back in January this year.