Mary Balogh
Mary Jo Putney
Amanda McCabe
Amanda Quick
Allison Lane
Georgette Heyer (especially These Old Shades and Devil's Cub)
Clare Darcy
Loretta Chase (especially Lord of Scoundrels)
Sarah MacLean (esp. The Rules of Scoundrels series)
Eloisa James (can be tearjerky)
Lisa Kleypas
Julia Quinn
Grace Burrowes
Anne Gracie (esp. the Perfect series)
Suzanne Enoch (try the Scandalous Brides series)
Sophie Barnes
Tessa Dare
Lynsay Sands (Scottish Highlanders and Devil of the Highlanders series)
Julie Garwood (The Secret and Lyon's Lady are my faves)
Stephanie Laurens (Bastion Club series)
And if you like your romances on the clean/sweet side, try the classic Signet regencies. Many of them are now available as ebooks, and this site has a good selection: http://www.regencyreads.com/online/. They aren't free, but it will give you authors to look for here.
I'm a librarian who loves Regency era novels. PM me if you want more information or more specific titles. I'm always happy to talk about books.