There are plenty of great options: Giggs, Scholes, Baresi, Maldini, Facchetti, Puyol, etc.
For me though, the greatest is Francesco Totti. The others above played for clubs who won multiple trophies, and all won the champions league at least once. Aside from a smattering of Coppa Italias and one Scudetto, Totti didn’t win anything with Rome.
For me, it’s easier for a top player to stay at a top club, rather than be a top player like Totti and stay at a club that was rarely considered the best in Serie A. For my money, he is the greatest one-club man of all time.
Who would you choose?
Yeah Maldini undoubtedly. How do you win a champions league in 3 different decades. That’s an unbelievable achievement. 2 were European cups on the old format, the other 3 CLs. To win 5. With multiple wins in both formats. 8 finals. 30 league games year in year out. Could play anywhere across the back line. Won it all with Milan a few times over. It would be hard to argue for anyone other than Maldini for me.