1. Lionel Messi: 
The
World Cup and Argentine is currently out of contract with the French giants Paris Saint-Germain, and as announced by the club's head coach Christophe Galtier, the player will be leaving the club at the end of the current season.
2. Sergio Ramos:
Solid during his days in Madrid, French club Paris Saint-Germain got to witness one of the greatest defenders of all-time in their club; however, Sergio Ramos is currently out of contract with the club and might as well be leaving the club this summer with Lionel Messi.
3. Karim Benzema:
Big Benz! As you may have guessed, Benzema is currently out of contract with the La Liga giants Real Madrid and is 80% sure of leaving the club this summer; however, we will allow time to ponder and decide on that. In the meantime, Karim Benzema is one of the players who are out of contract this summer.
4. Roberto Firmino:
Contributing to Liverpool's rich history of winning the UEFA Champions League in 2019, Roberto Firmino will be making his way out of the club this season, and as he is currently out of contract this summer,
5. Gundogan: 
A Germany international and Pep Guardiola's midfield specialist, Gundogan is also one of the top players who are out of contract this summer, although there has not been a definite decision on his future.
6. David De Gea:
Still doing his job for Manchester United, David De Gea is also one of the players who are out of contract this season, though it might be a last-minute decision to keep the Spaniard at the club.