1. Lionel Messi
Although Lionel Messi is expected to spend his entire career at Barcelona, you never know what might happen in the future.
If - and that's a big if - the Argentina international was to leave the Camp Nou within the next three years, he would be sold for an absolutely insane price.
Rumours suggest that there would even be one or two clubs willing to trigger his €250m release clause.
But will Messi ever decide to leave his beloved Barcelona? It seems unlikely.