Namesakes
Austrian Dukes and Emperors:
2 archdukes
Archduke Leopold IV (middle name Balthasar) 1657-1705 
Archduke Karl II (middle name Balthasar) 1711-1740
Bohemian Kings:
2 kings
King Leopold I (middle name Balthasar) 1656-1705
King Karel II (middle name Balthasar) 1711-1740
German Kings and Holy Roman Emperors:
2 king-emperors
King-Emperor Leopold I (middle name Balthasar) 1658-1705
King-Emperor Karl VI (middle name Balthasar) 1711-1740
Hungarian Kings and Queens:
2 kings
King Lipót I (middle name Balthasar) 1655-1705
King Károly III (middle name Balthasar) 1711-1740
Olympic Medalists:
1 silver
(silver) Balthasar Schwarm 1976 luge
Saints:
2 blessed
Blessed Baldassare of Chiavari (a.k.a. Balthasar) 1420-1492
Blessed Balthasar de Torres ?-1626
Shakespearian Characters:
4 characters
Balthasar Much Ado About Nothing
Balthasar Romeo and Juliet
Balthasar The Comedy of Errors
Balthasar The Merchant of Venice