#8 Gylfi Sigurdsson
It wasn't until 2012 when Spurs signed Sigurdsson from Hoffenheim that the midfielder actually got noticed. He had played well for Hoffenheim, which earned him the move in the first place, but was nowhere near the standard he would eventually become.
Unfortunately, though, his time at White Hart Lane wasn't the best, and he struggled to get into the star-studded first team. There was no doubting that he was a good player at this point, but with so many strong players already fighting for his position, it never looked as if it would work out.
Therefore, he was sold to Swansea City in 2014 for just under £10m, and it was here that he truly thrived. He played over 30 games each season for the Swans, showing just how key he was to their set-up, and notched up both a considerable amount of goals and assists. It was clear that without him in the squad, Swansea would have been relegated long ago.
However, when Swansea eventually did face the drop, Sigurdsson was offered a way out by Everton. The Toffees offered £45m for the Icelandic No. 10, and the deal was promptly accepted, given that the Swans were desperate for cash at this point.
His first season at Goodison Park was mediocre, as he scored four times and only assisted three; but this season, Sigurdsson has scored 12 goals and set-up four for his teammates. Despite being on the brink of his 30s, Sigurdsson is still showing that he's developing with every passing campaign.