#1 Marcos Alonso
The Spanish full-back's family constantly pops up when one goes through the history of Spanish football. His grandfather spent eight years at Real Madrid, with his father representing Atletico Madrid, Barcelona, and Spain at the senior level.
He joined Real Madrid's youth academy as a child and even made an appearance for the first team way back in 2009. Consequent spells with Bolton Wanderers, Fiorentina and a loan stint at Sunderland followed. On his return from England, he cemented his spot as a started with Fiorentina, as Chelsea's interest grew.
It took £24 million for the club to sign him and the player has become one of Antonio Conte's favorites. He has seamlessly slotted himself into the starting left-wing back position and amassed 48 appearances in the 2017/18 season.
His ability to bomb down the flanks and join the attacking player's with his goal-scoring prowess has been lauded in the Premier League and his performances have been instrumental in his team's successful FA Cup campaign.
He has had only one call-up to the international side so far, an 11-minute appearance against Argentina in March earlier this year. This made the Alonsos the first Spanish family to have three generations of internationals.
He was widely touted to make it to the final list, but Julen Lopetegui opted for Arsenal left-back Nacho Monreal instead. "Monreal has come with us many times. We know him well and we are convinced he will help us," said the manager when questioned over the decision.
Other notable exclusions: Alvaro Morata (Chelsea), Ander Herrera (Manchester United), Marc Bartra (Borrusia Dortmund), Javi Martinez (Bayern Munich), Hector Bellerin (Arsenal).