Namesakes
Bishops of Rome and the Popes:
3 popes, 1 antipope
Sylvester I 314-335 
Sylvester II 999-1003
Sylvester III 1045
Sylvester 1105-1111
Fictional Characters from Movies:
1 character
Sylvester 1945 Life with Feathers
Notable Actors and Entertainers:
2 actors
Sylvester McCoy 1943-
Sylvester Stallone 1946-
Notable Athletes:
1 ice hockey, 1 soccer
(ice hockey) P. K. Subban (a.k.a. Sylvester) 1989-
(soccer) Cyrus Christie (a.k.a. Sylvester) 1992-
Notable Businesspeople:
1 businessperson
William S. Harley (a.k.a. Sylvester) 1880-1943
Notable Musicians:
1 musician
Sly Stone (a.k.a. Sylvester) 1943-
Olympic Medalists:
1 gold
(gold) P. K. Subban (a.k.a. Sylvester) 2014 ice hockey
Rock and Roll Hall-of-Famers:
1 musician
Sly Stone (a.k.a. Sylvester) 1993 Sly and the Family Stone
Saints:
3 saints
Saint Sylvester I 285-335
Saint Sylvester Gozzolini 1177-1267
Saint Sylvester of Troina ?-1185