Shakespeare used
Gertrude for
Hamlet's mum, the queen of Denmark, so he seems to have associated it with northern Europe.
I find some of the entries in your 1796 list fascinating: Hierom, for instance, but not
Jerome. Strange! Rice I suppose is
Rhys. Could Benigma be
Benigna, if the printing is sometimes unclear? That would be less odd. As for
Fortune,
Hagar, Jacquet and Sisera ... who says the world hasn't improved?
I don't imagine the compiler of that list did original research as we would understand it: probably just liked names and noted them down when he encountered them. Nice chap!