Namesakes
Bishops of Rome and the Popes:
3 popes, 1 antipope
Callixtus I (a.k.a. Callistus) 217-222 
Callixtus II (a.k.a. Callistus) 1119-1124
Callixtus (a.k.a. Callistus) 1168-1178
Callixtus III (a.k.a. Callistus) 1455-1458
Saints:
2 saints, 1 blessed
Saint Callixtus I (a.k.a. Callistus) ?-222
Saint Callistus ?-1003
Blessed Calixtus Caravario (a.k.a. Callistus) ?-1930