Namesakes
Fictional Characters from Books:
1 character
Humbert Humbert 1955 Lolita 
Other Royalty:
2 princes, 1 king
Joachim of Prussia (middle name Humbert) 1890-1920 Prussia
Friedrich Karl of Prussia (middle name Humbert) 1893-1917 Prussia
Albert II of Belgium (middle name Humbert) 1993-2013 Belgium
Saints:
2 blessed
Blessed Humbert III 1136-1188
Blessed Humbert of Romans 1200-1277