It's not easy to find CDrama that end up with a happy ending, so the list is not very long (I strict remain on history if you need I can suggest Wuxia later).
Battle of Changsha it's a Republican era drama, set during WWII, I'll just say that is a masterpiece and a must watch, I couldn't watch any drama for weeks after I've finished.
Legend of Concubine Zhen Huan set in Qing dynasty. I know that the number of episodes could shock at first glance, but it's so so so good, this drama it's an experience trust me. Palace/harem dramas set in the Qing dynasty are difficult for the first approach of Historical drama (I saw your dramalist and I noted that you haven't watched this type of drama, so I must say it)
General and I set in the Three Kingdoms. There are some skippable scenes, but the love story, the chemistry and the passion between the leads are unbeatable, if you are curious watch some clips on youtube, you won't regret.
Legend of Lu Zhen if I don't remember wrong, it's set in the Tang dynasty. Cool drama with
Zanilia Zhao, love story on top and great palace intrigues.
Rookie agent rouge set in the Republican era. It's an action/spy drama, the love story is slow and steady.
The princess wei-young set in Northern Wei Dynasty. It's a revenge drama, everything it's beautiful from the costumes to the scenography to the leads, the story it's worth your time.
The story of Ming Lan this one is set in Song dynasty and it's still ongoing, so I don't know if ends up with a happy ending. It's such a beautiful drama, can bring you in the mentality and struggle of a woman in ancient China and it's the lightest of the drama that I suggest you (LOL).
If you need anything ask me :)