#4 Frank de Boer
He joined the club at the same time his brother did but Frank de Boer’s impact was much greater than Ronald. De Doer was a ball playing centre back before being a ball playing centre back was cool. During his 4 years at Barca de Boer was one of the best centre-halves in the world with his ability to play out of defence with the composure and accuracy of a midfielder and possessed the pace and technical prowess of a winger. Just like Kluivert, de Boer didn't win much during his time in Spain, just the since La Liga, compared to others on this list, but his pure quality puts him this high up.
After 215 appearances de Boer left for Galatasaray in 2003. De Boer will always be remembered with his elegance mixed with his tough tackling as one of the clubs great defenders. A successful stint that deserved more silverware.