Here are some useful resources for studying Handel and music in eighteenth-century England.
British Music Festivals Database
Handel Reference Database
Index to songs in 18th-century anthologies
Musicians' networks in 18th-century London
American Handel Society
Czech Handel Society
Handel Gesellschaft
Handel Hendrix House
Handel opera synopses
Händel-Haus Halle
London Handel Festival
GCHC catalogue
Manuscripts at the British Library
RISM
Golden Pages for musicologists
Vauxhall Gardens