Eden Hazard. Play a 4-2-3-1 him on the left of the 3, Inside Forward. You will thank me.
Igor Akinfeev. You need a solid goalkeeper.
Sime Vrsaljko, although I've found it difficult obtaining a work permit for him.
Lucas Digne.
Raphael Varane.
Thorgan Hazard.
Javier Pastore, definitely my favourite player in the game, if you play him correctly he turns out to be insane, for the first 6 months he isn't brilliant because he's settling in though.
Yaya Sanogo, best poacher in the game.
Khouma Babacar, beast.
There's a lot more, but they should get you started for the future.