AMR: Arjen Robben
Inexplicably sold to Real Madrid earlier in his career, Arjen Robben has gone on to become one of the best attacking players in the world, and should have been kept at Chelsea after a bright start, even if he had some troubles with injury.
AML: Eden Hazard
Another super skillful player, Eden Hazard is still at Chelsea and a vital part of how the Blues play.
AMC: Kevin De Bruyne
Stupidly let go for just £16m, Kevin De Bruyne quickly became one of the best creative players in Europe at Wolfsburg, before returning to the Premier League with Manchester City this summer in a stunning £55m deal.
FC: Romelu Lukaku
Sold for a big fee to Everton, but Chelsea would surely rather have the player instead, with Romelu Lukaku one of the best young strikers in the world and an ideal long-term replacement for Didier Drogba.