They are several world class players in the world that qualified for the 2018 world cup and below are some of them.
RUSSIA
Key player: Igor Akinfeev (CSKA Moscow).
SAUDI ARABIA
Key player: Mohammad Al-Sahlawi (Al-Nassr).
EGYPT
Key player: Mohamed Salah (Liverpool).
URUGUAY
Key player: Edinson Cavani (Paris Saint-Germain).
PORTUGAL
Cristiano Ronaldo (Real Madrid)
SPAIN
Key player: Andres Iniesta (Barcelona)
MOROCCO
Key player: Nabil Dirar (Fenerbahce)
IRAN
Key player: Sardar Azmoun (Rubin Kazan)
FRANCE
Key player: Mbappe (PSG)
AUSTRALIA
Key player: Mile Jedinak (Aston Villa)
PERU
Key player: Paolo Guerrero (Flamengo)
DENMARK
Key player: Christian Eriksen (Tottenham)
ARGENTINA
Key player: Lionel Messi (Barcelona)
ICELAND
Key player: Aron Gunnarsson (Cardiff City)
CROATIA
Key player: Luka Modric (Real Madrid)
NIGERIA
Key player: Alex Iwobi (Arsenal)
BRAZIL
Key player: Neymar (P S G).
SWITZERLAND
Key player: Xhaka ( Arsenal)
COSTA RICA
Key player: keylor Navas (Real Madrid)
SERBIA
Key player: Ivanovic ( zenith st Petersburg)
GERMANY
Key player: mesut Ozil (Arsenal)
MEXICO
Key player: chicharito ( Westham)
SWEDEN
Key player: Forsberg (Leipzig)
SOUTH KOREA
Key player: Son Heung-min (Tottenham)
BELGIUM
Key player: Eden Hazard ( Chelsea)
ENGLAND
Key player: Harry Kane (Tottenham)
PANAMA
Key player: Luis (Universitario)
TUNISIA
Key player:Msakni (Al Duhail)
POLAND
Key player: Lewandowski (Bayern Munich)
SENEGAL
Key player: Sadio mane ( Liverpool)
COLOMBIA
Key player: James Rodriguez ( Bayern Munich)
JAPAN
Key player: Kagawa ( Burusia Dortmund)
Hope you found it interesting, feel free to to me who don't deserve to be in the list and who I should replace him with.