Start by looking at our monarchy -
Elizabeth obviously,
Philip,
Charles,
William,
Henry nn
Harry.
George,
Edward,
Victoria,
Anne,
James,
Mary,
Richard . . . and so on.
Others that I'd class as having the same sort of (slightly upper-class) British vibe:
ArthurGeraldEdmundEdgarTristan (
Tristram even more so, possibly too much)
LaurenceLionelGarethJasper
EdithEleanor especially nn
NellAdaAliceLillianLouisaMatildaFlorenceCecily /
Cicely