Okay, because I made my earlier post about how I really do think more people in the cdrama fandom should watch pre-2020 cdramas.
(why 2020? it's a nice round year, but also, there was a big censorship overhaul around 2020-2021. Plus I feel like 2020-21 was when there was the influx into the cdrama fandom.)
Anyways - categories purely by me and not at all scientific. I have more, but I tried to keep this list to things that (I think) have subs.
Legend of Zhen Huan: yes, harem dramas aren't everyone's thing and I acknowledge it. But if you are going to watch one harem drama, make it this one. It is one of IMO the best character study revenge plot in cdramaland that really explores the concept of patriarchy and power and sisterhood. Bonus, certain scenes in more recent cdramas will suddenly click because Zhen Huan is *that* influential. One note: I recommend the viki version, which the subtitle team does a wonderful job in explaining the context for the numerous poetry that the characters use.
The Story of Minglan: you know the story of the unfavored daughter getting revenge on her evil stepmother and then finding love with a hot noblemen? yes, this is the OG. Except everyone is fleshed out and 3D and you feel like you're watching real people.
Battle of Changsha (available on YouTube, no idea where else): Republic era/WW2 epic, so utterly real, so utterly heartbreaking, flawlessly written and acted. Yang Zi's best work to date, IMO.
(I'll put in Nirvana in Fire and Advisor's Alliance -- but I"ll be honest -- male centric stories tend not to be my cup of tea even if they are very well made, but I can acknowledge that the quality is there.)
The Idol Historical (aka my genre):
Scarlet Heart (no, not the k-drama version that I slowly grew a grudge against. The OG cdrama with Liu Shi Shi, currently available on Iqiyi): it borderlines prestige (TM) for me, but it's categorized as an idol historical so I'll address it as such. Modern girl transmigrate to Qing dynasty, and the writing is so cerebral and it's ultimately a thought-provoking piece about keeping one's sense of self and identity, and the difficulty choices we make along the way. You don't have to ship anyone to enjoy this drama. Ignore the sequel.
Goodbye My Princess (I know there's an English version on YouTube): a grand romantic tragedy (I'm putting that in open disclaimer) about how a murderous bastard soft for one girl trope and love isn't enough. The fact that the ML is also the villain. And then get salty about Cheng Xingxu (ML's actor)'s subsequent projects with me. (addendum - if you enjoy this, the King's Woman with Zhang Binbin and Dilreba is also excellent).
Singing all along (I have a separate genre called "Ruby Lin dramas"): it's a fictionalized story of Emperor Guangwu of Han and Yin Lihua, and it definitely has the most resemblance to post 2020 idol historical romances, except the harem plot which is historically accurate and added some fantastic tension. I also adore the costuming, which had some heft (TM) to it.
Not Necessarily Quality but Fun (bonus: MLs are now uncles/fathers to the current batch idol dramas):
The Glamorous Imperial Doctress (on Netflix): is it quality? I'm not sure, but if you are watching the Princess's Gambit and wondering if you can take off all hinges, congratulations! I don't even know how to describe it, other than ... it's unhinged but in the most entertaining way. ML gets chained in a palace by SML.
General and I (on Viki): does it have bad blue/green screen? yes. Can Angelababy act? not really. Does she and Wallace Chung have insane chemistry and this drama is a romance novel coming to life with surprisingly a complicated story involving the SML? absolutely. (I have a whole list of Wallace Chung dramas, including My Sunshine and Too Late to Say I Love You, but I do think General and I seem to be a good starting point if you are used to watching post 2020 idol historical).
...don't ask me about xianxia, because it's not my genre. Although Chinese Paladin 3 (available now on Iqiyi) is fun with a legendary cast (seriously, the cast). Or wuxia, for that matter. Or moderns. But if you do want harem drama recommendations, I have about 5 more.