[zanjabila]

The Bridgertons series by Julia Quinn are great....

darker Still by Leanna Renee Hieber

Some really good Authors have been mentioned:
Julia Quinn
Eloisa James
G Heyers

try these ones too although they are not only YA

Anne Gracie
Anne Mallory
Carole Motimer
Elizabeth Boyle
Grace Burrowes
Julie Anne Long
Karen Hawkins
Kasey Micheals
Kate Noble
Kieran Maker
Lisa Kleypas
Meg (Patricia) Cabot
Olivia Parker
Sabrina Jeffries
Sarah Maclean
Stephanie Laurens
Suzanne Enoch

The Legacy Trilogy by Cayla Kluver

Carolyn Meyer is good

Try Cameron Dockey

You can try Cameron Dockey books. She remade famous fairy tale stories

I liked the prequels to nightshade series for kinda a historical romance feel. Loved the whole series by Andrea Cremer.

Some of these suggestion above are not YA like Julia Garwood although Georgette heyer's are squeaky clean so young adults can also enjoy it. I read almost all the YA historical romances and would recommend River of Time series by Lisa T Bergren, Julianne Donaldson and Melanie Dickerson

Maybe you'd like The Gemma Doyle Trilogy by Libba Bray. It's kind of the same genre as the Infernal Devices by Cassandra Clare