Namesakes
British Prime Ministers:
1 prime minister
Margaret Thatcher (a.k.a. Hilda) 1979-1990 
Hurricanes and Tropical Storms:
2 hurricanes
Hurricane Hilda 1955
Hurricane Hilda 1964
Olympic Medalists:
2 bronze, 2 silver
(silver) Hilda James 1920 swimming - 4x100 m freestyle relay
(silver) Hilda Strike 1932 100 m; 4x100 m relay
(bronze) Hilda Cameron 1936 4x100 m relay
(bronze) Hilda Gurney 1976 equestrian
Other Royalty:
1 grand duke
Marie-Adélaïde, Grand Duchess of Luxembourg (a.k.a. Hilda) 1912-1919 Luxembourg
Saints:
1 saint
Saint Hilda 614-680
Tolkien's Characters:
1 character
Hilda Bracegirdle (f)