I think these are the basic c-drama classics at this point:
Eternal Love/Love and Destiny/Eternal Love of Dream
Love Like the Galaxy
Till The End of the Moon
Goodbye My Princess (which I haven't seen because it doesn't end well)
Story of Yanxi Palace
Hidden Love
Well Intended Love
Story of Kunning Palace
Love Between Fairy and Devil
The Long Ballad
There are some other ones that I really didn't like but they're classics like
Love 020
You Are My Glory
The King's Woman
Love Is Sweet
Too Late to Say I Love You
Romance of Tiger and Rose