Judith McNaught's 'Whitney, My Love' is the best historical romance--perhaps the best of any romance genre--I ever read (I used to read a lot of historicals, "research" that came in handy when writing Angelus).

She'd have 2 or 3 in my top 10. Nearly all the rest would be LaVyrle, whom you've already discovered, although the two authors are very different.

I'm a sucker for the Regency; if you like those, try Catherine Mansfield.